Photovoltaic cell testing system

Abstract

The utility model relates to photovoltaic technical field provides a kind of photovoltaic cell test system, comprising: bearing plate, for bearing photovoltaic cell to be measured;At least one test light source, located in the side of bearing plate, for emitting test light to photovoltaic cell to be measured;Electrochromic plate, between test light source and bearing plate, for changing the light spot shape of test light emitted by test light source irradiated to photovoltaic cell to be measured.By controlling the voltage value of different parts of electrochromic plate, whether the light of different parts of electrochromic plate can be controlled, so that the shape of light spot on the surface of photovoltaic cell to be tested can be controlled, the time required to change light spot shape is reduced, and the efficiency of testing photovoltaic cell is improved.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic technology, and in particular to a photovoltaic cell testing system. Background Technology

[0002] In the production process of photovoltaic (PV) cells, various illumination tests are required, such as the External Quantum Efficiency (EQE) test. During illumination testing, the light spot on the surface of the PV cell under test needs to have different shapes. For this purpose, a grating is typically placed between the test light source and the PV cell. The test light generated by the test light source passes through the grating and illuminates the PV cell, resulting in a specific shape for the light spot on its surface.

[0003] In some cases, it is necessary to frequently change the shape of the light spot. The existing solution is to first remove the old grating and then set the new grating between the test light source and the photovoltaic cell under test. The time required to change the shape of the light spot is relatively long, which results in low efficiency in testing the photovoltaic cell. Utility Model Content

[0004] This invention provides a photovoltaic cell testing system that can shorten the time required to change the shape of the light spot during the testing process of photovoltaic cells, thereby improving the efficiency of photovoltaic cell testing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, a solar cell testing system is provided, comprising: a carrier plate for supporting a photovoltaic cell under test; at least one test light source located on one side of the carrier plate for emitting test light onto the photovoltaic cell under test; and an electrochromic plate located between the test light source and the carrier plate for changing the shape of the light spot emitted by the test light source onto the photovoltaic cell under test.

[0007] In conjunction with the first aspect, in some embodiments of the first aspect, the electrochromic panel includes: a panel body and a plurality of controllers, the panel body including a plurality of color-changing parts, one color-changing part being connected to one controller, the controller being used to control the voltage value of the connected color-changing part; the plurality of color-changing parts are arranged along a first direction, the total size of the plurality of color-changing parts along the first direction being equal to the size of the panel body, and the size of the color-changing parts along a second direction being equal to the size of the panel body, the first direction and the second direction intersecting.

[0008] In conjunction with the first aspect, in some embodiments of the first aspect, the size of the color-changing portion along the first direction is 3mm-7mm.

[0009] In conjunction with the first aspect, in some embodiments of the first aspect, the orthographic projection of the color-changing portion onto the plate body along the thickness direction of the plate body is a rectangle.

[0010] In conjunction with the first aspect, in some embodiments of the first aspect, the solar cell testing system further includes: a bias light source disposed on one side of a carrier plate for emitting bias light onto the photovoltaic cell under test.

[0011] In conjunction with the first aspect, in some embodiments of the first aspect, the wavelength of the bias light generated by the bias light source is 700nm-915nm.

[0012] In conjunction with the first aspect, in some embodiments of the first aspect, the test light source includes: a laser emitter located on one side of the carrier plate; a filter located between the electrochromic plate and the laser emitter; and a chopper located between the electrochromic plate and the filter.

[0013] In conjunction with the first aspect, in some embodiments of the first aspect, the solar cell testing system further includes: an image acquisition device disposed on one side of a support plate, used to acquire grayscale images of the photovoltaic solar cell under test.

[0014] In conjunction with the first aspect, in some embodiments of the first aspect, the cell testing system further includes: a lock-in amplifier connected to an image acquisition device.

[0015] In conjunction with the first aspect, in some embodiments of the first aspect, the carrier plate includes a first carrier portion and a second carrier portion, wherein the first carrier portion is used to carry the photovoltaic cell to be tested and the second carrier portion is used to carry the standard photovoltaic cell.

[0016] In this invention, an electrochromic plate is a device that can reversibly change its optical properties under the drive of an applied voltage. Different parts of the plate have different light transmittance under different voltages. By placing the electrochromic plate between the test light source and the carrier plate, and controlling the voltage values ​​of different parts of the electrochromic plate, the light transmittance of different parts of the electrochromic plate can be controlled. This allows control over the shape of the light spot that the test light irradiates onto the surface of the photovoltaic cell under test, reducing the time required to change the shape of the light spot and improving the efficiency of testing photovoltaic cells. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a battery cell testing system provided by this utility model;

[0018] Figure 2 A schematic diagram of the structure of an electrochromic plate provided by this utility model;

[0019] Figure 3 A schematic diagram of the structure of another electrochromic plate provided by this utility model;

[0020] Figure 4 This is a schematic diagram of the structure of an electrochromic plate provided by this utility model.

[0021] Figure label:

[0022] Solar cell testing system-10, carrier plate-101, first carrier part-1011, second carrier part-1012, test light source-102, laser emitter-1021, filter-1022, chopper-1023, electrochromic plate-103, plate body-1031, controller-1032, color-changing part-10311, electrochromic layer-10312, ion conductor layer-10313, ion storage layer-10314, bias light source-104, image acquisition device-105, lock-in amplifier-106, photovoltaic cell under test-20, standard photovoltaic cell-30. Detailed Implementation

[0023] In this embodiment of the invention, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this embodiment of the invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0024] Furthermore, to facilitate a clear description of the technical solutions of the embodiments of this utility model, the terms "first" and "second" are used in the embodiments of this utility model to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0025] It is understood that the term "embodiment" used throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of the present invention. Therefore, the various embodiments throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It is understood that in the various embodiments of the present invention, the sequence number of each process does not imply the order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0026] It is understood that in this utility model, "when," "if," and "if" all refer to the corresponding processing that will be carried out under certain objective circumstances, and are not limited to a time, nor do they require that there must be a judgment action when it is implemented, nor do they mean that there are other limitations.

[0027] It is understood that some optional features in the embodiments of this utility model can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the device given in the embodiments of this utility model can also implement these features or functions, which will not be elaborated here.

[0028] In this utility model, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments and implementation methods of this utility model, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments and between the implementation methods of different embodiments are consistent and can be mutually referenced. The technical features in different embodiments and between the implementation methods of different embodiments can be combined according to their inherent logical relationships to form new embodiments, implementation methods, implementation methods, or implementation approaches. The following embodiments of this utility model do not constitute a limitation on the scope of protection of this utility model.

[0029] In the production process of photovoltaic (PV) cells, various illumination tests are required, such as the External Quantum Efficiency (EQE) test. During illumination testing, the light spot on the surface of the PV cell under test needs to have different shapes. For this purpose, a grating is typically placed between the test light source and the PV cell. The test light generated by the test light source passes through the grating and illuminates the PV cell, resulting in a specific shape for the light spot on its surface.

[0030] In some cases, it is necessary to frequently change the shape of the light spot. The existing solution is to first remove the old grating and then set the new grating between the test light source and the photovoltaic cell under test. The time required to change the shape of the light spot is relatively long, which results in low efficiency in testing the photovoltaic cell.

[0031] To address the aforementioned problems, this utility model provides a battery cell testing system, such as... Figure 1As shown, the photovoltaic cell testing system 10 includes: a carrier plate 101 for carrying the photovoltaic cell 20 to be tested; at least one test light source 102 located on one side of the carrier plate 101 for emitting test light onto the photovoltaic cell 20 to be tested; and an electrochromic plate 103 located between the test light source 102 and the carrier plate 101 for changing the shape of the light spot emitted by the test light source on the photovoltaic cell 20 to be tested.

[0032] In this invention, the electrochromic plate 103 is a device that can reversibly change its optical properties under the drive of an applied voltage. Different parts of the plate have different light transmittance under different voltages. The electrochromic plate 103 is placed between the test light source 102 and the carrier plate 101. By controlling the voltage values ​​of different parts of the electrochromic plate 103, the light transmittance of different parts of the electrochromic plate 103 can be controlled. This allows control over the shape of the light spot that the test light irradiates onto the surface of the photovoltaic cell under test, reducing the time required to change the shape of the light spot and improving the efficiency of testing the photovoltaic cell.

[0033] like Figure 2 or Figure 3 As shown, the electrochromic panel 103 includes a panel body 1031 and multiple controllers 1032. The panel body 1031 includes multiple color-changing parts 10311, and each color-changing part 10311 is connected to a controller 1032. The controller 1032 is used to control the voltage value of the connected color-changing part 10311. In this way, each color-changing part 10311 can be controlled individually, thereby improving the flexibility of controlling the electrochromic panel 103.

[0034] Multiple controllers 1032 can be integrated into one device, or, as... Figure 2 or Figure 3 As shown, multiple controllers 1032 can also be set individually, and this utility model does not impose specific limitations on this.

[0035] like Figure 4 As shown, the plate 1031 mainly includes an electrochromic layer 10312, an ion conductor layer 10313, and an ion storage layer 10314.

[0036] The electrochromic layer 10312 is the core functional layer of the plate 1031, containing electrochromic materials. When a voltage is applied, ions and electrons are injected into the electrochromic layer 10312, and the electrochromic materials undergo a reduction reaction, thereby changing color and affecting the light transmittance.

[0037] The ion conductor layer 10313, also known as the electrolyte layer, is responsible for conducting ions between the electrochromic layer 10312 and the electrochromic layer 10312.

[0038] The ion storage layer 10314 stores ions to provide ions to the electrochromic layer 10312 in order to maintain the charge balance of the entire plate 1031.

[0039] In addition to the electrochromic layer 10312, the ion conductor layer 10313, and the ion storage layer 10314, the plate body 1031 may also include other structures. For example, the plate body 1031 may also include two transparent conductive layers, with the electrochromic layer 10312, the ion conductor layer 10313, and the ion storage layer 10314 disposed between the two transparent conductive layers to protect the electrochromic layer 10312, the ion conductor layer 10313, and the ion storage layer 10314.

[0040] Electrochromic materials may include at least one of tungsten trioxide, molybdenum oxide, titanium dioxide, niobium oxide, nickel oxide, or iridium oxide. Of course, electrochromic materials may also include other materials, and this utility model does not impose specific limitations on them.

[0041] The following is a brief explanation of the color-changing control method of the electrochromic panel 103:

[0042] When the color-changing portion 10311 of the plate 1031 is in a transparent state, to make the color-changing portion 10311 of the plate 1031 opaque, firstly, a positive voltage is applied to the corresponding color-changing portion 10311 of the plate 1031; then, ions stored in the ion storage layer 10314 migrate to the electrochromic layer 10312 through the ion conductor layer 10313, and electrons are also injected into the electrochromic layer 10312; then, the electrochromic material undergoes a reduction reaction after receiving ions and electrons, resulting in a change in the optical properties of the color-changing portion 10311, with the color deepening and the transparency decreasing.

[0043] If it is necessary to restore the transparency of the color-changing part 10311 of the plate 1031, a reverse voltage can be applied to the corresponding color-changing part 10311 of the plate 1031. Ions and electrons will migrate in the opposite direction in the color-changing part 10311 of the plate 1031, and the electrochromic material in the electrochromic layer 10312 will undergo an oxidation reaction, so that the color-changing part 10311 of the plate 1031 will return to its original transparent state.

[0044] Along the thickness direction of the plate 1031, the orthographic projection of the color-changing portion 10311 onto the plate 1031 can be of any shape. For example, the orthographic projection of the color-changing portion 10311 onto the plate 1031 can be a rectangle, triangle, trapezoid, or circle. Of course, the orthographic projection of the color-changing portion 10311 onto the plate 1031 can also be other regular or irregular shapes; this invention does not impose specific limitations in this regard. Preferably, as... Figure 1 or Figure 2As shown, the orthographic projection of the color-changing part 10311 onto the plate 1031 is a rectangle. Since the rectangle has a high degree of regularity, the convenience of arranging the color-changing part 10311 can be improved.

[0045] In some embodiments, such as Figure 2 As shown, multiple color-changing parts 10311 are arranged along a first direction. Along the first direction, the total size h1 of the multiple color-changing parts 10311 is equal to the size h2 of the plate 1031. Along the second direction, the size h3 of the color-changing parts 10311 is equal to the size h4 of the plate 1031. The first and second directions intersect. Thus, when testing the photovoltaic cell 20 under test, the shape of the light spot is usually required to be elongated. Since the color-changing parts 10311 are arranged along the first direction, and the size h3 of the color-changing parts 10311 along the second direction is equal to the size h4 of the plate 1031 along the second direction, the orthographic projection of the color-changing parts 10311 on the plate 1031 is elongated. Therefore, the number of controlled color-changing parts 10311 can be reduced, thereby improving the efficiency of testing the photovoltaic cell.

[0046] The angle between the second direction and the first direction can be a right angle, or the angle between the second direction and the first direction can be an acute angle, or the angle between the second direction and the first direction can be an obtuse angle. This utility model does not impose any specific limitations on this.

[0047] Along the first direction, the size h5 of the color-changing part 10311 is 3mm-7mm, for example 3mm, 4mm, 5mm, 6mm, 7mm. Of course, the size h5 of the color-changing part 10311 can also have other values, and this utility model does not make specific limitations in this regard.

[0048] Thus, by setting the size h5 of the color-changing part 10311 within a suitable range, it is possible to avoid both a reduction in the precision of the color change of the electrochromic panel 103 due to an excessively large size h5 and a small number of color-changing parts 10311, and an increase in the cost of the photovoltaic cell testing system 10 due to an excessively small size h5 and a large number of color-changing parts 10311 and controllers 1032. Setting a suitable size h5 for the color-changing part 10311 can improve the precision of the color change of the electrochromic panel 103 and reduce the cost of the photovoltaic cell testing system 10.

[0049] In some other embodiments, such as Figure 3 As shown, multiple color-changing parts 10311 are arranged along a first direction and a second direction respectively. Along the first direction, the total size h1 of the multiple color-changing parts 10311 is equal to the size h2 of the plate body 1031. Along the second direction, the total size h6 of the multiple color-changing parts 10311 is equal to the size h4 of the plate body 1031.

[0050] Thus, since the color-changing portions 10311 are arranged along the first and second directions respectively, by pixelating the color-changing portions 10311, the flexibility of controlling the shape of the light spot can be improved, thereby increasing the efficiency of testing photovoltaic cells.

[0051] A detailed description of the dimension h5 of the color-changing part 10311 in this embodiment can be found in the parameter. Figure 2 To avoid redundancy, the relevant descriptions in the illustrated embodiments will not be repeated here.

[0052] Along the second direction, the dimension h7 of the color-changing part 10311 is 3mm-7mm, for example, 3mm, 4mm, 5mm, 6mm, or 7mm. Of course, the dimension h7 of the color-changing part 10311 can also have other values, and this invention does not impose specific limitations on this. Thus, by setting the dimension h7 of the color-changing part 10311 within a suitable range, it is possible to avoid both excessively large dimensions (h7) resulting in a smaller number of color-changing parts 10311 and reduced precision of the color-changing effect of the electrochromic panel 103, and excessively small dimensions (h7) resulting in a larger number of color-changing parts 10311 and a larger number of controllers 1032, thereby increasing the cost of the photovoltaic cell testing system 10. Setting a suitable dimension h7 for the color-changing part 10311 can improve the precision of the color-changing effect of the electrochromic panel 103 and reduce the cost of the photovoltaic cell testing system 10.

[0053] exist Figure 3 In the embodiment shown, one controller 1032 can control the voltage value of each color-changing part 10311 in a row of color-changing parts 10311. For specific implementation schemes, refer to existing related schemes. This utility model does not impose specific limitations on this.

[0054] The carrier plate 101 includes a first carrier part 1011 and a second carrier part 1012. The first carrier part 1011 is used to carry the photovoltaic cell 20 to be tested, and the second carrier part 1012 is used to carry the standard photovoltaic cell 30.

[0055] The standard photovoltaic cell 30 is a solar cell with precisely known performance parameters that has undergone rigorous calibration and standardization. Thus, since the second support portion 1012 of the support plate 101 carries the standard photovoltaic cell 30, when testing the photovoltaic cell 20 under test, the standard photovoltaic cell 30 can be used to calibrate the test results of the photovoltaic cell 20 under test, and can also be used to detect the light intensity emitted by the bias light source 104 or the test light source 102, ensuring that each test is conducted under completely consistent and standard lighting conditions, thereby improving the testing accuracy of the photovoltaic cell 20 under test.

[0056] The photovoltaic cell under test 20 and the standard photovoltaic cell 30 can be TOPCon cells, BC cells, or HJT cells. Of course, the photovoltaic cell under test 20 and the standard photovoltaic cell 30 can also be other types of cells, and this utility model does not impose specific limitations on them.

[0057] The number of test light sources 102 can be one or more, and this utility model does not impose a specific limitation on this.

[0058] With multiple test light sources 102, each emits test light with a different wavelength. This allows for simultaneous testing of the photovoltaic cell 20 under multiple different conditions, improving the testing efficiency.

[0059] like Figure 1 As shown, the test light source 102 includes: a laser emitter 1021 located on one side of the carrier plate 101; a filter 1022 located between the electrochromic plate 103 and the laser emitter 1021; and a chopper 1023 located between the electrochromic plate 103 and the filter 1022.

[0060] After the laser emitter 1021 emits laser light, the filter 1022 filters out the frequency-doubled light and stray light in the laser, improving the purity of the laser light illuminating the photovoltaic cell 20 under test. The chopper 1023 converts the laser light from continuous light into pulsed light, allowing the laser light from the laser emitter 1021 to illuminate the photovoltaic cell 20 under test in the form of pulsed light. By coordinating the laser emitter 1021, filter 1022, and chopper 1023, high-purity pulsed light can be emitted to the photovoltaic cell 20 under test. Simultaneously, because the light illuminating the surface of the photovoltaic cell 20 under test is pulsed light, the irradiation time of the photovoltaic cell 20 under test is extremely short, reducing the heat generated by the photovoltaic cell 20 under test and minimizing the impact of the photovoltaic cell 20's temperature on the test results, thereby improving the accuracy of the test of the photovoltaic cell 20 under test.

[0061] The laser emitter 1021 is an electro-optical device capable of generating laser light, emitting laser light with good directionality, monochromaticity, coherence, and brightness. For example, the laser emitted by the laser emitter 1021 is white, thus simulating the working state of the photovoltaic cell 20 under test in a real environment and improving the accuracy of the test.

[0062] The laser emitter 1021 can be a free-electron laser, a liquid laser, a semiconductor laser, or a gas laser. Of course, the laser emitter 1021 can also be other types of laser emitters 1021, and this utility model does not impose any specific limitations on this.

[0063] Filter 1022 is a device that can select a specific wavelength of laser light from multiple different wavelengths and suppress or eliminate other wavelengths of laser light.

[0064] The filter 1022 can be a long-pass filter 1022, which allows laser light with a wavelength longer than a certain specific value to pass through, while blocking laser light with a wavelength shorter than that specific value.

[0065] The chopper 1023 can convert the laser emitted by the laser emitter 1021 from continuous light into test light. By adjusting the operating frequency of the chopper 1023, the pulse frequency of the test light illuminating the photovoltaic cell 20 under test can be adjusted.

[0066] The chopper 1023 can be a rotary blade chopper 1023, a vibrating blade chopper 1023, an electro-optical chopper 1023, or an acousto-optical chopper 1023. Of course, the chopper 1023 can also be other types of choppers 1023, and this utility model does not impose specific limitations on them.

[0067] like Figure 1 As shown, the solar cell testing system 10 also includes a bias light source 104, which is disposed on one side of the carrier plate 101 and is used to emit bias light to the photovoltaic cell 20 under test.

[0068] The optical power density of the bias light source 104 can be between 0.4 Sun and 0.6 Sun, for example, 0.4 Sun, 0.5 Sun, or 0.6 Sun. Of course, the optical power density of the bias light source 104 can also be other values, and this invention does not impose specific limitations on this. Thus, setting the optical power density of the bias light source 104 within a suitable range can avoid both situations where the optical power density is too low, failing to eliminate the capacitance effect of the photovoltaic cell 20 under test, thereby reducing the accuracy of the test, and situations where the optical power density is too high, causing the surface of the photovoltaic cell 20 under test to overheat, thus reducing the accuracy of the test. Setting a suitable optical power density for the bias light source 104 can improve the accuracy of the test of the photovoltaic cell 20 under test.

[0069] The bias light source 104 can be an array laser light source, an LED array light source, a halogen tungsten light source, or a bromine tungsten light source. Of course, the bias light source 104 can also be other types of light sources, and this utility model does not impose specific limitations on this. Preferably, the bias light source 104 is an array laser light source. In this way, since the control response speed of the array laser light source is faster, the testing efficiency of the photovoltaic cell 20 under test can be improved. At the same time, the laser generated by the array laser light source can directly excite the photovoltaic cell 20 under test to generate electron-hole pairs, reduce the heat energy generated by the photovoltaic cell 20 under test during the exciton relaxation process, reduce the heat generated by the photovoltaic cell 20 under test due to bias light irradiation, and further improve the accuracy of the testing of the photovoltaic cell 20 under test.

[0070] The wavelength of the bias light generated by the bias light source 104 can be between 700nm and 915nm, such as 700nm, 750nm, 800nm, 850nm, 900nm, and 915nm. Of course, the wavelength of the bias light generated by the bias light source 104 can also be other values, and this invention does not impose specific limitations on this. Thus, setting the wavelength of the bias light generated by the bias light source 104 within a suitable range can avoid insufficient excitation depth of the photovoltaic cell 20 under test due to an excessively short wavelength, which would affect the accuracy of the test. It can also avoid excessively long wavelengths where the bias light directly penetrates the photovoltaic cell 20 under test, preventing effective excitation and thus affecting the accuracy of the test. Setting a suitable wavelength for the bias light generated by the bias light source 104 can improve the accuracy of the test of the photovoltaic cell 20 under test.

[0071] For example, when the photovoltaic cell 20 under test is a BC cell, the wavelength of the bias light generated by the bias light source 104 is 808nm. Thus, for the BC cell, the optimal excitation wavelength of the bias light is 808nm, and the incident depth of the bias light can reach 80um, which is well matched with the thickness of the BC cell and improves the irradiation effect of the bias light.

[0072] like Figure 1 As shown, the solar cell testing system 10 also includes an image acquisition device 105, located on one side of the support plate 101, for acquiring grayscale images of the photovoltaic cell 20 under test. Thus, after acquiring the grayscale image of the photovoltaic cell 20 under test, the image acquisition device 105 can send it to the processor, so that the processor can analyze the grayscale image and obtain the test results of the photovoltaic cell 20 under test.

[0073] The image acquisition device 105 can also be called a photoluminescence imager or a PL imager.

[0074] The image acquisition device 105 can be a scanning PL imager, an area array camera PL imager, an infrared thermal imager PL imager, or a microscope integrated PL imager. Of course, the image acquisition device 105 can also be other types of equipment, and this utility model does not impose specific limitations on it.

[0075] The grayscale image of the photovoltaic cell 20 under test is an image that contains only the brightness information of the photovoltaic cell 20 under test, but not the color information of the photovoltaic cell 20 under test. It can be used to analyze the performance or defects of the photovoltaic cell 20 under test.

[0076] like Figure 1 As shown, the solar cell testing system 10 also includes a lock-in amplifier 106, which is connected to the image acquisition device 105. Thus, the lock-in amplifier 106 can remove noise from the signal acquired by the image acquisition device 105, improve the signal-to-noise ratio, and thereby improve the accuracy of the test of the photovoltaic cell 20 under test.

[0077] The lock-in amplifier 106 can be an analog lock-in amplifier 106 or a digital lock-in amplifier 106, and this utility model does not impose any specific limitations on it.

[0078] With only one test light source 102, the lock-in amplifier 106 is a single-channel lock-in amplifier 106. Thus, since there is only one pulse light source, using a single-channel lock-in amplifier 106 to remove noise from the signal acquired by the image acquisition device 105 can reduce the cost of the cell testing system 10.

[0079] When there are multiple test light sources 102, the lock-in amplifier 106 is a multi-channel lock-in amplifier 106. Thus, when multiple test lights of different wavelengths illuminate the photovoltaic cell under test 20, the multi-channel lock-in amplifier 106 can separate the signal corresponding to each wavelength of test light and remove noise from each signal, improving the signal-to-noise ratio of the signal acquired by the image acquisition device 105, thereby improving the accuracy and efficiency of the test of the photovoltaic cell under test 20.

[0080] The solar cell testing system 10 may also include a light-transmitting plate and a fixture. In practical applications, the photovoltaic cell 20 to be tested can be placed between the light-transmitting plate and the carrier plate 101, and then the photovoltaic cell 20 to be tested, the light-transmitting plate and the carrier plate 101 can be fixed by the fixture. The bias light and the test light are irradiated onto the surface of the photovoltaic cell 20 to be tested through the light-transmitting plate. In this way, foreign objects or fixtures can be prevented from damaging the photovoltaic cell 20 to be tested, thereby improving the safety of the photovoltaic cell 20 to be tested.

[0081] Based on the solar cell testing system 10 provided by this utility model, the photovoltaic cell 20 under test can be tested through the following multiple steps:

[0082] First, the photovoltaic cell 20 to be tested undergoes pretreatment such as cleaning.

[0083] This ensures that the surface of the photovoltaic cell 20 under test is clean, preventing dust and other impurities on the surface of the photovoltaic cell 20 from affecting the test results.

[0084] Next, the photovoltaic cell 20 to be tested is placed on the first support part 1011 of the support plate 101, and the standard photovoltaic cell 30 is placed on the second support part 1012 of the cooling plate.

[0085] This ensures that the photovoltaic cell under test 20 and the standard photovoltaic cell 30 are in the same environment, thus improving the effectiveness of the calibration test results.

[0086] Next, the bias light source 104 is turned on, so that the bias light emitted by the bias light source 104 shines on the photovoltaic cell under test 20, so that the photovoltaic cell under test 20 is in working state.

[0087] Next, the laser emitter 1021, filter 1022 and chopper 1023 are turned on, and the electrochromic plate 103 is turned on. The light transmittance of different color-changing parts 10311 of the electrochromic plate 103 is controlled by the control method provided in the above specific embodiment, so that the shape of the light spot illuminating the photovoltaic cell 20 under test is different.

[0088] Secondly, during the process of the laser emitter 1021 emitting laser light onto the surface of the photovoltaic cell 20 under test, the image acquisition device 105 and the lock-in amplifier 106 work together to acquire the photoluminescence signal of the photovoltaic cell 20 under different light spots and convert it into a grayscale image.

[0089] Finally, the grayscale image is transmitted to the processor in the solar cell testing system 10. The processor has a specific program built in, which can analyze the performance or defects of the photovoltaic cell 20 under test based on the grayscale image and obtain the analysis results.

[0090] Although the present invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, the disclosure, and the appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0091] Although the present invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and drawings are merely exemplary descriptions of the present invention as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the present invention. Clearly, those skilled in the art can make various alterations and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and modifications.

Claims

1. A photovoltaic cell testing system, characterized in that, The photovoltaic cell testing system includes: The support plate is used to support the photovoltaic cells to be tested; At least one test light source is located on one side of the support plate and is used to emit test light onto the photovoltaic cell under test; An electrochromic plate, located between the test light source and the carrier plate, is used to change the shape of the light spot emitted by the test light source when it illuminates the photovoltaic cell under test.

2. The photovoltaic cell testing system according to claim 1, characterized in that, The electrochromic panel includes: Board and multiple controllers; The plate includes multiple color-changing parts, and each color-changing part is connected to a controller. The controller is used to control the voltage value of the connected color-changing parts. The plurality of color-changing parts are arranged along a first direction, and the total size of the plurality of color-changing parts along the first direction is equal to the size of the plate. Along a second direction, the size of the color-changing parts is equal to the size of the plate. The first direction and the second direction intersect.

3. The photovoltaic cell testing system according to claim 2, characterized in that, Along the first direction, the size of the color-changing part is 3mm-7mm.

4. The photovoltaic cell testing system according to claim 2, characterized in that, Along the thickness direction of the plate, the orthographic projection of the color-changing part on the plate is a rectangle.

5. The photovoltaic cell testing system according to claim 1, characterized in that, The photovoltaic cell testing system also includes: A bias light source is located on one side of the carrier plate and is used to emit bias light to the photovoltaic cell under test.

6. The photovoltaic cell testing system according to claim 5, characterized in that, The wavelength of the bias light generated by the bias light source is 700nm-915nm.

7. The photovoltaic cell testing system according to claim 1, characterized in that, The test light source includes: A laser emitter is located on one side of the support plate; A filter is located between the electrochromic plate and the laser emitter; A chopper is located between the electrochromic plate and the filter.

8. The photovoltaic cell testing system according to claim 1, characterized in that, The photovoltaic cell testing system also includes: An image acquisition device is located on one side of the support plate and is used to acquire grayscale images of the photovoltaic cell under test.

9. The photovoltaic cell testing system according to claim 8, characterized in that, The photovoltaic cell testing system also includes: A lock-in amplifier is connected to the image acquisition device.

10. The photovoltaic cell testing system according to any one of claims 1-9, characterized in that, The support plate includes a first support part and a second support part. The first support part is used to support the photovoltaic cell under test, and the second support part is used to support a standard photovoltaic cell.

Images