Testing method for photovoltaic cell

Abstract

The invention relates to the field of photovoltaic cell testing, particularly provides a testing method for a photovoltaic cell, and aims to solve the problems that more probes are adopted in the existing multi-main-grid cell testing, more shielding is caused, and the testing result is inaccurate. In order to achieve the purpose, the test method for the photovoltaic cell comprises the following steps: controlling a probe to electrically connect the photovoltaic cell with an electronic load; obtaining the ratio of the shielding area of the probe to the effective area of the photovoltaic cell; controlling the excitation light source to carry out light infiltration irradiation on the photovoltaic cell; controlling the test light source to irradiate the photovoltaic cell with preset test light intensity; the light intensity of the excitation light source is controlled to be compensation light intensity, and the compensation light intensity is equal to the product of the preset test light intensity and the ratio; and controlling the electronic load to carry out voltage scanning on the photovoltaic cell. The light intensity of the excitation light source is adjusted according to the ratio so as to compensate the light intensity of the test light source, and the accuracy and reliability of the test result are improved.

Description

Technical Field

[0001] The invention relates to the field of photovoltaic cell testing, and specifically provides a testing method for photovoltaic cells. Background Art

[0002] Semiconductor optoelectronic devices such as photovoltaic cells are generally tested according to the requirements of the corresponding standards. Among them, the IV test of photovoltaic cells is a key link in evaluating their performance and quality. By measuring the current output at different voltages and drawing the IV curve, key parameters such as open circuit voltage and short circuit current can be obtained, so as to comprehensively evaluate the photoelectric conversion efficiency and stability of photovoltaic cells. This test not only helps manufacturers monitor product quality during the production process and ensure that each battery meets the established standards, but also provides important data support for the design and operation and maintenance of photovoltaic systems. At the same time, IV testing is also an important tool for the research and development of new photovoltaic cell technologies. Through data analysis and feedback, it promotes the technological progress and development of the photovoltaic industry.

[0003] In the prior art, when photovoltaic cells and other devices are subjected to IV testing, steady-state simulators are generally used. Steady-state simulators are divided into conventional light sources and LED light sources. Conventional light sources have a short lifespan and LED light sources have a large spectral mismatch. Steady-state simulators are expensive and have a short service life.

[0004] However, when testing multi-busbar batteries, since the multi-busbar battery test uses more probes, more obstructions are caused, resulting in inaccurate test results.

[0005] Accordingly, the art needs a new technical solution to solve the above problems. Summary of the invention

[0006] The present invention aims to solve the above technical problems and the problem that the existing multi-busbar battery test uses a large number of probes, resulting in a large number of obstructions and inaccurate test results.

[0007] The present invention provides a testing method for photovoltaic cells, which comprises: controlling a probe to form an electrical connection between the photovoltaic cell and an electronic load; obtaining a ratio between a shielding area of ​​the probe and an effective area of ​​the photovoltaic cell; controlling an excitation light source to perform light immersion irradiation on the photovoltaic cell; controlling a test light source to irradiate the photovoltaic cell with a preset test light intensity; controlling the light intensity of the excitation light source to a compensation light intensity, wherein the compensation light intensity is equal to the product of the preset test light intensity and the ratio; and controlling the electronic load to perform a voltage scan on the photovoltaic cell.

[0008] When adopting the above technical solution, the ratio of the blocked area of ​​the probe to the effective area of ​​the photovoltaic cell is obtained, and the light intensity of the excitation light source is adjusted according to the ratio to compensate for the light intensity of the test light source. By accurately calculating and applying the compensated light intensity, it is ensured that the effective irradiation area of ​​the photovoltaic cell by the test light source matches the actual test requirements, thereby significantly improving the accuracy and reliability of the test results.

[0009] In a specific implementation of the above-mentioned test method for photovoltaic cells, the step of performing light immersion irradiation includes: controlling the excitation light source to continuously irradiate the photovoltaic cell with the preset test light intensity for a preset time period.

[0010] When the above technical solution is adopted, the detailed design of the light immersion irradiation step ensures that the photovoltaic cell reaches a stable state before the formal test, reducing the test error caused by the unstable initial state of the cell. Through continuous irradiation for a preset time period, the photovoltaic cell can fully respond to the test light source, improving the stability and repeatability of the test data.

[0011] In the specific implementation of the above-mentioned test method for photovoltaic cells, the preset test light intensity is adjustable, ranging from 950W / m 2 -1050W / m 2 、750W / m 2 -850W / m 2 、550W / m 2 -650W / m 2 、350W / m 2 -450W / m 2 、150W / m 2 -250W / m 2 、50W / m 2 -150W / m 2 .

[0012] When the above technical solution is adopted, a reasonable preset test light intensity range is set, which not only ensures that the intensity of the test light source matches the actual working environment of the photovoltaic cell, but also avoids the influence of excessive or weak light intensity on the test results.

[0013] In a specific implementation of the above-mentioned test method for photovoltaic cells, the range of the preset time period is greater than or equal to 1 s.

[0014] When the above technical solution is adopted, the preset time period greater than or equal to 1 second ensures that the photovoltaic cell has enough time to reach a stable state, thereby improving the accuracy of the test results.

[0015] In a specific embodiment of the above-mentioned test method for photovoltaic cells, the photovoltaic cell includes a plurality of cells and grid lines located between the plurality of cells, and the probe includes a first probe connected to the grid lines and a second probe connected to the backlight surface of the photovoltaic cell.

[0016] When the above technical solution is adopted, the first probe and the second probe are used to connect with the photovoltaic cell, which makes the connection with the photovoltaic cell more convenient and improves the test efficiency.

[0017] In a specific implementation of the above-mentioned test method for photovoltaic cells, the illumination wavelength range of the excitation light source and the test light source is the same.

[0018] When the above technical solution is adopted, by ensuring that the illumination wavelength range of the excitation light source and the test light source is the same, the test error caused by spectral mismatch is avoided. This design enables the test light source to more accurately simulate the lighting conditions in the actual working environment, thereby improving the reliability of the test results.

[0019] In a specific implementation of the above-mentioned test method for photovoltaic cells, the quality grade of the excitation light source is not higher than the quality grade of the test light source.

[0020] In the case of adopting the above technical solution, an excitation light source with a lower quality grade than the test light source is used for light immersion irradiation, which reduces the test cost. At the same time, since the excitation light source is only used to initially stabilize the state of the photovoltaic cell, its quality requirements are relatively low and will not have a significant impact on the final test results.

[0021] In a specific implementation of the above-mentioned testing method for photovoltaic cells, the step of controlling the electronic load to perform a voltage scan on the photovoltaic cell further includes: controlling the electronic load to perform a voltage scan on the photovoltaic cell within a preset voltage range; wherein the preset voltage range includes -12V to 12V.

[0022] When the above technical solution is adopted, the testing method can comprehensively evaluate the performance of photovoltaic cells under different voltages.

[0023] In a specific implementation of the above-mentioned test method for photovoltaic cells, before turning on the excitation light source and the test light source, the test method further includes: calibrating the excitation light source and the test light source.

[0024] When the above technical solution is adopted, the excitation light source and the test light source are calibrated before the test to ensure the accuracy and stability of the test light source, effectively avoiding the test error caused by the unstable performance of the light source and improving the reliability of the test result.

[0025] In a specific implementation of the above-mentioned test method for photovoltaic cells, the step of calibrating the excitation light source and the test light source includes: controlling the excitation light source or the test light source to irradiate the standard battery with the preset test light intensity, and obtaining the short-circuit current Isc1 of the standard battery; comparing the short-circuit current Isc1 with the calibration current Isc0; and determining whether the corresponding excitation light source or the test light source is qualified based on the comparison result.

[0026] When the above technical solution is adopted, the light source is quantitatively verified by comparing the short-circuit current of a standard battery, so that it can be accurately determined whether the light source is qualified.

[0027] In a specific implementation of the above-mentioned test method for photovoltaic cells, when (Isc1-Isc0) / Isc0≤±1%, the corresponding excitation light source or the test light source is judged to be qualified; otherwise, the corresponding excitation light source or the test light source is judged to be unqualified.

[0028] When the above technical solution is adopted, when the short-circuit current deviation is within ±1%, the light source is determined to be qualified, thereby ensuring the accuracy and reliability of the test light source.

[0029] In a specific implementation of the above-mentioned test method for photovoltaic cells, the ratio of the time interval for the excitation light source to switch from the preset test light intensity to the compensation light intensity to the test duration for performing the voltage scan is less than or equal to 1 / 50.

[0030] When the above technical solution is adopted, the continuity and stability of the test process are ensured by controlling the ratio between the time interval of switching the light intensity of the excitation light source and the duration of the voltage scanning test. This design reduces the test error caused by the switching of the light source and improves the accuracy and reliability of the test data.

[0031] In a specific implementation of the above-mentioned test method for photovoltaic cells, the test duration ranges from 10 ms to 500 ms.

[0032] When the above technical solution is adopted, the reasonable range of the test time not only ensures the adequacy of the test process, but also avoids the waste of resources caused by excessively long test time.

[0033] In a specific implementation of the above-mentioned test method for photovoltaic cells, the voltage scanning rate is less than or equal to 5V / ms.

[0034] When the above technical solution is adopted, the upper limit of the voltage scanning rate is set to avoid the problem of unstable test data caused by too fast scanning rate. This design makes the test process smoother and easier to control, and improves the accuracy and reliability of the test data.

[0035] In a specific implementation of the above-mentioned testing method for photovoltaic cells, the control method further includes: respectively detecting the temperature and humidity of the test environment; respectively comparing the measured temperature and humidity with a preset temperature threshold and a preset humidity threshold; and adjusting the temperature and humidity of the test environment based on the comparison result so that they comply with the preset temperature threshold and the preset humidity threshold, wherein the preset temperature threshold is 23°C-27°C, and the preset humidity threshold is 65%-75%.

[0036] When the above technical solution is adopted, the consistency and stability of the test conditions are ensured by monitoring and adjusting the temperature and humidity of the test environment, which effectively avoids the influence of environmental factors on the test results and improves the accuracy and repeatability of the test results.

[0037] Solution 1. A testing method for photovoltaic cells, characterized in that the testing method comprises:

[0038] Controlling the probe to electrically connect the photovoltaic cell with an electronic load;

[0039] Obtaining a ratio between a shielding area of ​​the probe and an effective area of ​​the photovoltaic cell;

[0040] Controlling an excitation light source to perform light soaking irradiation on the photovoltaic cell;

[0041] Controlling the test light source to irradiate the photovoltaic cell with a preset test light intensity;

[0042] Controlling the light intensity of the excitation light source to a compensation light intensity, wherein the compensation light intensity is equal to the product of the preset test light intensity and the ratio;

[0043] The electronic load is controlled to perform voltage scanning on the photovoltaic cell.

[0044] Solution 2. The photovoltaic cell testing method according to Solution 1 is characterized in that the step of performing light soaking irradiation comprises:

[0045] The excitation light source is controlled to continuously irradiate the photovoltaic cell with the preset test light intensity for a preset time period.

[0046] Scheme 3. The testing method for photovoltaic cells according to Scheme 1 or 2 is characterized in that the preset test light intensity is adjustable, and the range includes 950W / m2-1050W / m2, 750W / m2-850W / m2, 550W / m2-650W / m2, 350W / m2-450W / m2, 150W / m2-250W / m2, and 50W / m2-150W / m2.

[0047] Solution 4. The photovoltaic cell testing method according to Solution 2 is characterized in that the range of the preset time period is greater than or equal to 1s.

[0048] Solution 5. The testing method for photovoltaic cells according to Solution 1 is characterized in that the photovoltaic cell includes a plurality of cell sheets and grid lines located between the plurality of cell sheets, and the probe includes a first probe connected to the grid lines and a second probe connected to the backlight surface of the photovoltaic cell.

[0049] Solution 6. The testing method for photovoltaic cells according to Solution 1 is characterized in that the illumination wavelength range of the excitation light source and the test light source is the same.

[0050] Solution 7. The testing method for photovoltaic cells according to Solution 1 is characterized in that the quality grade of the excitation light source is not higher than the quality grade of the test light source.

[0051] Solution 8. The photovoltaic cell testing method according to Solution 1 is characterized in that the step of controlling the electronic load to perform voltage scanning on the photovoltaic cell further comprises:

[0052] Controlling the electronic load to perform voltage scanning on the photovoltaic cell within a preset voltage range;

[0053] Wherein, the preset voltage range includes -12V to 12V.

[0054] Solution 9. The testing method for photovoltaic cells according to Solution 1 is characterized in that, before turning on the excitation light source and the test light source, the testing method also includes: calibrating the excitation light source and the test light source.

[0055] Solution 10. The photovoltaic cell testing method according to Solution 9 is characterized in that the step of calibrating the excitation light source and the test light source comprises:

[0056] Controlling the excitation light source or the test light source to illuminate the standard battery with the preset test light intensity, and obtaining the short-circuit current Isc1 of the standard battery;

[0057] Comparing the short-circuit current Isc1 with a rated current Isc0; and

[0058] Based on the comparison result, it is determined whether the corresponding excitation light source or the test light source is qualified.

[0059] Solution 11. The testing method for photovoltaic cells according to Solution 10 is characterized in that:

[0060] When (Isc1-Isc0) / Isc0≤±1%, the corresponding excitation light source or the test light source is determined to be qualified;

[0061] Otherwise, the corresponding excitation light source or the test light source is determined to be unqualified.

[0062] Scheme 12. The testing method for photovoltaic cells according to Scheme 2 is characterized in that the ratio between the time interval for the excitation light source to switch from the preset test light intensity to the compensation light intensity and the test duration for performing the voltage scan is less than or equal to 1 / 50.

[0063] Solution 13. The testing method for photovoltaic cells according to Solution 12 is characterized in that the test duration ranges from 10ms to 500ms.

[0064] Scheme 14. The testing method for photovoltaic cells according to Scheme 1 is characterized in that the voltage scanning rate is less than or equal to 5V / ms.

[0065] Solution 15. The photovoltaic cell testing method according to Solution 1, wherein the control method further comprises:

[0066] Detect the temperature and humidity of the test environment respectively;

[0067] Comparing the measured temperature and humidity with a preset temperature threshold and a preset humidity threshold, respectively;

[0068] Based on the comparison result, the temperature and humidity of the test environment are adjusted to meet the preset temperature threshold and the preset humidity threshold,

[0069] The preset temperature threshold is 23° C.-27° C., and the preset humidity threshold is 65%-75%. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0071] Figure 1 It is a structural schematic diagram of a test bench for photovoltaic cells of the present invention;

[0072] Figure 2 It is a schematic flow chart of a testing method for photovoltaic cells of the present invention;

[0073] Figure 3 It is a schematic diagram of a flow chart of calibrating an excitation light source and a test light source in a test method for photovoltaic cells of the present invention;

[0074] Figure 4It is a flow chart of an embodiment of the present invention for verifying an excitation light source and a test light source in a test method for photovoltaic cells;

[0075] Figure 5 It is a schematic diagram of a flow chart of adjusting a test environment in a test method for photovoltaic cells according to the present invention;

[0076] Figure 6 It is a flow chart of an embodiment of adjusting the temperature of a test environment in a test method for photovoltaic cells according to the present invention;

[0077] Figure 7 It is a flow chart of an embodiment of the present invention for adjusting the humidity of the test environment in the test method for photovoltaic cells.

[0078] List of reference numerals: 1 - test light source; 2 - excitation light source; 3 - adjustment platform; 4 - loading platform. DETAILED DESCRIPTION

[0079] The preferred embodiments of the present application are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present application and are not used to limit the scope of protection of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0080] It should be noted that, in the description of this application, unless otherwise clearly specified and limited, the terms "set", "connection", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or other connections; it can be directly connected or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, "multiple" refers to at least two. It should be understood that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0081] In order to solve the problem that the existing multi-main-grid battery test uses more probes, causes more shielding, and leads to inaccurate test results, the present invention provides a testing method for photovoltaic cells, the testing method comprising: controlling the probe to form an electrical connection between the photovoltaic cell and the electronic load (step S101); obtaining the ratio between the shielding area of ​​the probe and the effective area of ​​the photovoltaic cell (step S103); controlling the excitation light source to perform light immersion irradiation on the photovoltaic cell (step S105); controlling the test light source to irradiate the photovoltaic cell with a preset test light intensity (step S107); controlling the light intensity of the excitation light source to a compensation light intensity, the compensation light intensity being equal to the product of the preset test light intensity and the ratio (step S109); and controlling the electronic load to perform a voltage scan on the photovoltaic cell (step S111).

[0082] Figure 1 Schematic diagram of the structure of the test bench for photovoltaic cells of the present invention. Figure 1 As shown, in one or more embodiments, the test bench of the present invention includes a test light source 1, an excitation light source 2, an adjustment platform 3, a stage 4, a probe and an electronic load. The stage 4 is used to place a photovoltaic cell. The test light source 1 and the excitation light source 2 are both arranged toward the photovoltaic cell on the stage 4, and the number of the excitation light sources 2 is four, two excitation light sources 2 are located on the left side of the test light source 1, and the other two excitation light sources 2 are located on the right side of the test light source 1. Alternatively, the number of the excitation light sources 2 can be one, two, three or more, as long as the photovoltaic cell can be light-soaked and the current of the photovoltaic cell can be stimulated. The photovoltaic cell includes a plurality of cells and a grid line located between the plurality of cells, and the probe includes a first probe connected to the grid line and a second probe connected to the backlight surface of the photovoltaic cell. The first probe and the second probe are connected to the photovoltaic cell, so that the connection with the photovoltaic cell is more convenient and the test efficiency is improved. The electronic load is connected to the probe, and the probe is connected to the photovoltaic cell. By controlling the electronic load, the voltage at both ends of the photovoltaic cell changes, and the current flowing through the photovoltaic cell changes. It should be noted that the electronic load is a programmable electronic load or an electronic dummy load, which is an electronic device that can simulate the behavior of a real load. It can absorb electrical energy and consume it in a specific way according to preset parameters and conditions. The specific model of the electronic load can be selected as needed. The adjustment platform 3 is located on the lower side of the stage 4, and the adjustment platform 3 can control the temperature and humidity of the test environment of the photovoltaic cell. The temperature and humidity of the tested photovoltaic cell are within the set parameters. It should be noted that the specific structure of the adjustment platform 3 can be selected by those skilled in the art as needed.

[0083] It should be further explained that the configuration of the test bench is not unique, and those skilled in the art can select the specific configuration of the test bench based on specific application scenarios. For example, a light averaging plate can be provided between the test light source 1 and the stage 4 to convert the light emitted by the test light source 1 into parallel light.

[0084] In one or more embodiments, the illumination wavelength range of the excitation light source 2 is the same as that of the test light source 1. By ensuring that the illumination wavelength range of the excitation light source 2 is the same as that of the test light source 1, the test error caused by spectral mismatch is avoided. This design enables the test light source 1 to more accurately simulate the lighting conditions in the actual working environment, thereby improving the reliability of the test results. The quality grade of the excitation light source 2 is not higher than the quality grade of the test light source 1. Using an excitation light source 2 with a quality grade lower than that of the test light source 1 for light immersion irradiation reduces the test cost. At the same time, since the excitation light source 2 is only used to preliminarily stabilize the state of the photovoltaic cell, its quality requirements are relatively low and will not have a significant impact on the final test results. Alternatively, the quality grade of the excitation light source 2 may also be equal to the quality grade of the test light source 1.

[0085] Figure 2 FIG. 1 is a flow chart of a method for testing photovoltaic cells according to the present invention. Figure 2 As shown, in one or more embodiments, after the test method for photovoltaic cells of the present invention is started, step S101 is first executed, that is, the probe is controlled to form an electrical connection between the photovoltaic cell and the electronic load. For example, when the photovoltaic cell is placed on the stage, the probe includes a first probe and a second probe, the first probe is controlled to be connected to the grid line of the light-facing surface of the photovoltaic cell, the second probe is controlled to be connected to the backlight surface of the photovoltaic cell, and the other ends of the first probe and the second probe are electrically connected to the electronic load, thereby forming an electrical connection between the photovoltaic cell and the electronic load. Then step 103 is executed to obtain the ratio between the blocking area of ​​the probe and the effective area of ​​the photovoltaic cell. For example, the blocking area of ​​the probe on the light-facing surface of the photovoltaic cell and the effective area of ​​the light-facing surface of the photovoltaic cell are obtained by an imaging device, and the ratio of the blocking area to the effective area is obtained by calculation. The excitation light source is controlled to perform light soaking irradiation on the photovoltaic cell (step 105). The test light source is controlled to irradiate the photovoltaic cell with a preset test light intensity (step 107). For example, the preset test light intensity is 1000W / m 2 , control the test light source to 1000W / m 2 Irradiate the photovoltaic cell. Control the light intensity of the excitation light source to the compensation light intensity, which is equal to the product of the preset test light intensity and the ratio (step 109). Finally, control the electronic load to perform voltage scanning on the photovoltaic cell (step 111).

[0086] like Figure 2As shown, in one or more embodiments, step 103, obtains the ratio between the blocked area of ​​the probe and the effective area of ​​the photovoltaic cell. Preferably, the blocked area is the total area of ​​the blocked areas of the probes on the light-facing surface of the photovoltaic cell. The effective area of ​​the photovoltaic cell is the total area of ​​the light-facing surface of the photovoltaic cell. Alternatively, the blocked area may also be the total area of ​​the blocked areas of the probes on the light-facing surface of the photovoltaic cell minus the area of ​​the blocked grid line portion; the effective area of ​​the photovoltaic cell is the total area of ​​the light-facing surface of the photovoltaic cell minus the area of ​​the grid line portion. It should be noted that the blocked area of ​​the probe and the effective area of ​​the photovoltaic cell can be measured by an optical camera or other suitable method.

[0087] like Figure 2 As shown, in one or more embodiments, the test light source is controlled to irradiate the photovoltaic cell with a preset test light intensity (step S107). Preferably, the preset test light intensity is 1000 W / m 2 Specifically, the test light source is controlled to be turned on and the light source is 1000W / m 2 The test light intensity is irradiated to the photovoltaic cell. It should be noted that the light intensity of the test light source is controlled to be 1000W / m 2 In fact, due to the setting of the test light source itself, the actual light intensity of the test light source is different from 1000W / m 2 There will be some deviation, as long as the actual light intensity of the test light source is 950W / m 2 -1050W / m 2 Of course, the actual light intensity of the test light source can be controlled to be 750W / m 2 -850W / m 2 、550W / m 2 -650W / m 2 、350W / m 2 -450W / m 2 、150W / m 2 -250W / m 2 、50W / m 2 -150W / m 2 etc., to test the photovoltaic cell under different lighting conditions. It should be further noted that the above light intensity range is exemplary, and those skilled in the art can adjust the light intensity range according to specific needs to meet the test requirements.

[0088] like Figure 2 As shown, in one or more embodiments, the excitation light source is controlled to perform light soaking irradiation on the photovoltaic cell (step S105). The light soaking irradiation step includes: controlling the excitation light source to continuously irradiate the photovoltaic cell with a preset test light intensity for a preset time period. Preferably, the preset test light intensity is 1000W / m 2The range of the preset time period is greater than or equal to 1s. Specifically, in step S105, the light intensity of the excitation light source is controlled to be 1000W / m 2 , and continuously irradiate the photovoltaic cell for more than or equal to 1 second. The carriers in the photovoltaic cell are excited, so that the ion migration reaches a stable arrangement state. Alternatively, the light intensity of the excitation light source may not use the preset test light intensity, that is, the light intensity of the excitation light source when irradiating the photovoltaic cell with light can be different from the light intensity of the test light source when irradiating the photovoltaic cell.

[0089] It should be noted that the light intensity of the excitation light source is controlled to be 1000W / m 2 In fact, due to the setting of the excitation light source itself, the actual light intensity of the excitation light source is about 1000W / m 2 There will be some deviation, as long as the actual light intensity of the excitation light source is around 950W / m 2 -1050W / m 2 Of course, the light intensity of the excitation light source can be controlled to 200W / m 2 、300W / m 2 , 500W / m 2 etc., to test the photovoltaic cell under different lighting conditions. It should also be noted that the photovoltaic cell is continuously irradiated for greater than or equal to 1 second to ensure that the ion migration in the photovoltaic cell reaches a stable arrangement state. Those skilled in the art can set the continuous irradiation time of the photovoltaic cell according to the characteristics of the photovoltaic cell, which can be 0.5s, 0.6s, 1.2s or other times.

[0090] In one or more embodiments, step S109 controls the light intensity of the excitation light source to a compensation light intensity, wherein the compensation light intensity is equal to the product of the preset test light intensity and the ratio. For example, the preset test light intensity is 1000 W / m 2 , the ratio is 0.1, then the compensation light intensity is 100W / m 2 Specifically, in step S109, the light intensity of the excitation light source is controlled from 1000 W / m 2 Adjust to 100W / m 2 .

[0091] In one or more embodiments, step S111, the step of controlling the electronic load to perform voltage scanning on the photovoltaic cell further includes: controlling the electronic load to perform voltage scanning on the photovoltaic cell within a preset voltage range; wherein the preset voltage range is -12V to 12V. Specifically, the electronic load is adjusted to perform voltage scanning on the photovoltaic cell within the range of -12V to 12V, the voltage and corresponding current of the photovoltaic cell are recorded, and the performance of the photovoltaic cell is judged by the voltage and current. It should be noted that the preset voltage scanning range can be 0-3V or 2V-10V, etc., and the specific preset voltage range can be set according to the specific situation of the photovoltaic cell and the test requirements. In one or more embodiments, the test duration of the voltage scan is preferably 300ms. The reasonable range of the test duration not only ensures the adequacy of the test process, but also avoids the waste of resources caused by too long test time. Of course, the test duration of the voltage scan can be other suitable values ​​between 10ms-500ms, for example, 20ms, 50ms, 100ms, 110ms, etc. In one or more embodiments, the rate of the voltage scan is preferably 3V / ms. Of course, the voltage scanning rate should be less than or equal to 5V / ms. Setting the upper limit of the voltage scanning rate avoids the problem of unstable test data caused by too fast scanning rate. This design makes the test process smoother and easier to control, and improves the accuracy and reliability of the test data.

[0092] In one or more embodiments, the ratio between the time interval of the excitation light source switching from the preset test light intensity to the compensation light intensity and the test duration of the voltage scan is less than or equal to 1 / 50. By controlling the ratio between the time interval of the excitation light source intensity switching and the voltage scan test duration, the continuity and stability of the test process are ensured. This design reduces the test error caused by the light source switching and improves the accuracy and reliability of the test data.

[0093] In one or more embodiments, the order of step S107 and step 109 can be interchanged, and step 109 is first performed to control the light intensity of the excitation light source to the compensation light intensity, wherein the compensation light intensity is equal to the product of the preset test light intensity and the ratio; and then step S107 is performed to control the test light source to irradiate the photovoltaic cell with the preset test light intensity. Before performing step 107, ensure that the light intensity on the photovoltaic cell is always greater than or equal to 20% of the preset test light intensity.

[0094] Regarding the execution order of the steps, it should be noted that although the present invention describes that steps S101 and S103 are executed first and then step S105, this is only an example. Without departing from the basic principles of the present invention, those skilled in the art can adjust the execution order of different steps as needed, for example, first execute step S105 and then execute steps S101 and S103. The adjusted solution is equivalent to the technical solution described in the present invention, and therefore will also fall within the protection scope of the present invention.

[0095] In one or more embodiments, before turning on the excitation light source and the test light source, the test method further includes: calibrating the excitation light source and the test light source. Through the above-mentioned setting, the accuracy and stability of the test light source can be ensured, and the test error caused by the unstable performance of the light source can be effectively avoided, thereby improving the reliability of the test result. Alternatively, the excitation light source and the test light source may not be calibrated, as long as it can be ensured that the light source meets the test requirements.

[0096] Figure 3 The figure is a schematic diagram of the flow of calibrating the excitation light source and the test light source in the test method for photovoltaic cells of the present invention. Figure 3 As shown, in one or more embodiments, the step of verifying the excitation light source and the test light source includes: controlling the excitation light source or the test light source to irradiate the standard battery with a preset test light intensity, and obtaining the short-circuit current Isc1 of the standard battery (step S201). It should be noted that the standard battery is a standard battery cell of the same type as the photovoltaic cell, and the standard battery is irradiated with a preset test light intensity by the excitation light source or the test light source, and the short-circuit current Isc1 of the standard battery is obtained. The short-circuit current Isc1 is compared with the calibration current Isc0 (step S202); wherein the calibration current Isc0 is the standard current that should be generated under the preset test light intensity. Based on the comparison result, it is determined whether the corresponding excitation light source or test light source is qualified (step S203). By comparing the short-circuit current of the standard battery, the excitation light source or the test light source is quantitatively verified, and it is possible to accurately determine whether the light source is qualified.

[0097] It should be noted that the test environment for verifying the excitation light source and the test light source can be configured the same as the test environment for testing the calibration current of the standard battery. Specifically, when verifying the excitation light source, only the excitation light source is turned on, and when verifying the test light source, only the test light source is turned on.

[0098] Figure 4 FIG. 1 is a flow chart of an embodiment of the present invention for verifying an excitation light source and a test light source in a test method for photovoltaic cells. Figure 4As shown, in one or more embodiments, the step of verifying the excitation light source and the test light source includes: S301, controlling the excitation light source or the test light source to irradiate the standard battery with a preset test light intensity. SS302, obtaining the short-circuit current Isc1 and the calibration current Isc0 of the standard battery. S303, judging whether (Isc1-Isc0) / Isc0≤±1% is established, if so, executing S304, if not, executing S305. S304, judging that the corresponding excitation light source or test light source is qualified. S305, judging that the corresponding excitation light source or test light source is unqualified. After judging that it is unqualified, replace the standard battery, and verify the excitation light source and the test light source again. If it is unqualified again, debug the unqualified excitation light source or test light source. Avoid inaccurate verification caused by damage to the standard battery. Alternatively, the judgment condition can also be (Isc1-Isc0) / Isc0≤±2% or (Isc1-Isc0) / Isc0≤±2.5%, etc.

[0099] Figure 5 FIG. 1 is a flow chart of adjusting the test environment in the test method for photovoltaic cells of the present invention. Figure 5 As shown, in one or more embodiments, the control method further includes: S401, detecting the temperature and humidity of the test environment respectively; for example, detecting the temperature and humidity of the test environment by a temperature sensor and a humidity sensor. S402, comparing the measured temperature and humidity with a preset temperature threshold and a preset humidity threshold respectively; for example, comparing the measured temperature with the preset temperature threshold, and comparing the measured humidity with the preset humidity threshold. S403, adjusting the temperature and humidity of the test environment based on the comparison result so that it meets the preset temperature threshold and the preset humidity threshold. The preset temperature threshold is 23°C-27°C, and the preset humidity threshold is 65%-75%. For example, when the measured temperature is higher than the preset temperature threshold, the test environment is cooled; when the measured temperature is lower than the preset temperature threshold, the test environment is heated. When the measured humidity is higher than the preset humidity threshold, the test environment is dehumidified; when the measured humidity is lower than the preset humidity threshold, the test environment is humidified. By monitoring and adjusting the temperature and humidity of the test environment, the consistency and stability of the test conditions are ensured. The influence of environmental factors on the test results is effectively avoided, and the accuracy and repeatability of the test results are improved. Alternatively, the preset temperature threshold can be set according to the test requirements, such as 20°C-30°C, 15°C-22°C, etc. Alternatively, the preset humidity threshold can be set according to the test requirements, such as 60%-70%, 50%-62%, etc.

[0100] Figure 6 FIG. 1 is a flow chart of an embodiment of the present invention for adjusting the temperature of the test environment in the test method for photovoltaic cells. Figure 6As shown, in one or more embodiments, S501, detect the temperature of the test environment; S502, determine whether the temperature of the test environment is within the preset temperature threshold, if so, end, otherwise execute S503; S503, determine whether the temperature of the test environment is greater than the maximum value of the preset temperature threshold, if so, execute S504, otherwise execute S505; S504, cool down the test environment; S505, heat up the test environment. Until the temperature of the test environment is within the preset temperature threshold.

[0101] Figure 7 FIG. 1 is a flow chart of an embodiment of the present invention for adjusting the humidity of the test environment in the test method for photovoltaic cells. Figure 7 As shown, in one or more embodiments, S601, detect the humidity of the test environment; S602, determine whether the humidity of the test environment is within the preset humidity threshold, if so, end, otherwise execute S603; S603, determine whether the humidity of the test environment is greater than the maximum value of the preset humidity threshold, if so, execute S604, otherwise execute S605; S604, dehumidify the test environment; S605, humidify the test environment. Until the humidity of the test environment is within the preset humidity threshold.

[0102] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims of the present application, any one of the claimed embodiments may be used in any combination.

[0103] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A testing method for photovoltaic cells, characterized in that: The test method includes: Controlling the probe to electrically connect the photovoltaic cell with an electronic load; Obtaining a ratio between a shielding area of ​​the probe and an effective area of ​​the photovoltaic cell; Controlling an excitation light source to perform light soaking irradiation on the photovoltaic cell; Controlling the test light source to irradiate the photovoltaic cell with a preset test light intensity; Controlling the light intensity of the excitation light source to a compensation light intensity, wherein the compensation light intensity is equal to the product of the preset test light intensity and the ratio; The electronic load is controlled to perform voltage scanning on the photovoltaic cell.

2. The testing method for photovoltaic cells according to claim 1, characterized in that: The steps of performing light soaking irradiation include: The excitation light source is controlled to continuously irradiate the photovoltaic cell with the preset test light intensity for a preset time period.

3. The testing method for photovoltaic cells according to claim 1 or 2, characterized in that: The preset test light intensity is adjustable, ranging from 950W / m 2 -1050W / m 2 、750W / m 2 -850W / m 2 、550W / m 2 -650W / m 2 、350W / m 2 -450W / m 2 、150W / m 2 -250W / m 2 , 50W / m 2 -150W / m 2 .

4. The testing method for photovoltaic cells according to claim 2, characterized in that: The range of the preset time period is greater than or equal to 1s.

5. The testing method for photovoltaic cells according to claim 1, characterized in that: The photovoltaic cell comprises a plurality of cells and grid lines between the plurality of cells, and the probe comprises a first probe connected to the grid lines and a second probe connected to the backlight surface of the photovoltaic cell.

6. The testing method for photovoltaic cells according to claim 1, characterized in that: The excitation light source and the test light source have the same illumination wavelength range.

7. The testing method for photovoltaic cells according to claim 1, characterized in that: The quality grade of the excitation light source is not higher than the quality grade of the test light source.

8. The testing method for photovoltaic cells according to claim 1, characterized in that: The step of controlling the electronic load to perform voltage scanning on the photovoltaic cell further comprises: Controlling the electronic load to perform voltage scanning on the photovoltaic cell within a preset voltage range; Wherein, the preset voltage range includes -12V to 12V.

9. The testing method for photovoltaic cells according to claim 1, characterized in that: Before turning on the excitation light source and the test light source, the test method further includes: The excitation light source and the test light source are calibrated.

10. The testing method for photovoltaic cells according to claim 9, characterized in that: The step of calibrating the excitation light source and the test light source comprises: Controlling the excitation light source or the test light source to illuminate the standard battery with the preset test light intensity, and obtaining the short-circuit current Isc1 of the standard battery; Comparing the short-circuit current Isc1 with a rated current Isc0; and Based on the comparison result, it is determined whether the corresponding excitation light source or the test light source is qualified.

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