Photovoltaic Cell Testing Method

Abstract

The present invention provides a method for testing a photovoltaic cell, comprising the steps of: sequentially selecting a first reference cell and a second reference cell to calibrate the spectral response of a light source, one of the selected first reference cell and second reference cell being provided with a band-pass filter, and the other of the selected first reference cell and second reference cell being provided with a long-pass filter, the light transmittance of the band-pass filter being greater than 35% for light in a light-transmitting band of 330 to 720 nanometers, and the light transmittance of the long-pass filter being greater than 10% for light in a light-transmitting band of 700 nanometers or more; and measuring an electrical property curve of a cell under test at a position in an optical path of the light source. Thus, the technical problem derived from the error of the spectral response mismatch factor of the existing photovoltaic cell is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic component testing, and particularly to a photovoltaic cell testing method that can reduce the spectral response mismatch factor (MMF) error of a stacked solar cell. Background Art

[0002] The photovoltaic effect is widely applied in the renewable energy industry. For example, solar photovoltaic devices have characteristics such as energy conservation, safety, no moving components, low maintenance requirements, and adjustable power generation according to demand, and are gradually becoming energy systems that are developed and built.

[0003] In practice, when a solar cell or module is tested under standard test conditions, whether the measurement result using a reference cell is accurate has a significant impact on the product yield of solar photovoltaic manufacturers. Although related technologies have been proposed in the past, the spectral response mismatch factor error of the test results is relatively large and still needs to be improved.

[0004] In view of this, it is necessary to provide a technical solution different from the prior art to solve the problems existing in the prior art. Summary of the Invention

[0005] An embodiment of the present invention provides a photovoltaic cell testing method for solving the technical problems derived from the spectral response mismatch factor error of existing photovoltaic cells.

[0006] To solve the above problems, one aspect of the present invention provides a photovoltaic cell testing method, including the steps of: sequentially selecting a first reference cell and a second reference cell to calibrate the spectral response of a light source, one of the selected first reference cell and second reference cell has a band-pass filter, and the other of the selected first reference cell and second reference cell has a long-pass filter, the light transmittance of the band-pass filter is greater than 35% for light with a wavelength range of 330 to 720 nanometers in the light transmission band, and the light transmittance of the long-pass filter is greater than 10% for light with a wavelength of 700 nanometers or more in the light transmission band; and measuring an electrical curve of a test cell at a position in an optical path of the light source.

[0007] According to an embodiment of the present invention, the step of sequentially selecting the first reference cell and the second reference cell to calibrate the spectral response of the light source includes the steps of: selecting the first reference cell and the second reference cell according to a current-limiting layer selected from a top cell layer and a bottom cell layer of the test cell, if the current-limiting layer is the top cell layer, the selected first reference cell has the band-pass filter and the selected second reference cell has the long-pass filter, if the current-limiting layer is the bottom cell layer, the selected first reference cell has the long-pass filter and the selected second reference cell has the band-pass filter.

[0008] According to an embodiment of the present invention, the step of calibrating the spectral response of the light source by sequentially using the first reference cell and the second reference cell includes: configuring the light source to have a first light component with a wavelength within the optical wavelength range of a light-emitting diode; placing the first reference cell at the position in the optical path of the light source, configuring the light source to add a second light component with an intensity within the optical intensity range of a xenon lamp, such that the optoelectronic characteristics of the first reference cell are equal to a first calibration characteristic; and placing the second reference cell at the position in the optical path of the light source, and adjusting the light intensity of the first light component such that the optoelectronic characteristics of the second reference cell are greater than a second calibration characteristic.

[0009] According to an embodiment of the present invention, the wavelength of the first light component when the current-limiting layer is the top cell layer is different from the wavelength of the first light component when the current-limiting layer is the bottom cell layer.

[0010] According to an embodiment of the present invention, the wavelength of the first light component when the current-limiting layer is the top cell layer is within an infrared light wavelength range.

[0011] According to an embodiment of the present invention, the first reference cell and the second reference cell are respectively a calibrated reference cell. The first calibration characteristic is the photocurrent value indicated on a first calibration report of the first reference cell after calibration under a solar light intensity of 1000 watts per square meter. The second calibration characteristic is the photocurrent value indicated on a second calibration report of the second reference cell after calibration under a solar light intensity of 1000 watts per square meter.

[0012] According to an embodiment of the present invention, after making the optoelectronic characteristics generated by the second reference cell greater than the second calibration characteristic, the photovoltaic cell testing method further includes the steps of: measuring the optical characteristics of the light source, where the optical characteristics include the spectral response of the first light component and the spectral response of the second light component.

[0013] According to an embodiment of the present invention, the photovoltaic cell testing method further includes the steps of: measuring an external quantum efficiency of the top cell layer of the cell under test; measuring an external quantum efficiency of the bottom cell layer of the cell under test; integrating the external quantum efficiency of the top cell layer with respect to a standard solar spectral response AM1.5G to obtain a top cell short-circuit current density; integrating the external quantum efficiency of the bottom cell layer with respect to the standard solar spectral response AM1.5G to obtain a bottom cell short-circuit current density; determining whether the top cell short-circuit current density is less than the bottom cell short-circuit current density. If the determination is yes, selecting the top cell layer as the current-limiting layer; if the determination is no, selecting the bottom cell layer as the current-limiting layer.

[0014] According to an embodiment of the present invention, the first reference cell and the second reference cell each have a packaging window, and the packaging window is configured to be provided with the long-pass filter or the band-pass filter.

[0015] According to an embodiment of the present invention, the battery under test is a stacked solar cell.

[0016] The photovoltaic cell testing method of the present invention can, according to the different current-limiting layers of the battery under test, sequentially select a reference cell equipped with the band-pass filter or the long-pass filter as the basis for calibrating the spectral response of the light source. After testing the electrical characteristics of the battery under test with the spectral response of the calibrated light source, a test result with a low spectral response mismatch factor error can be obtained. Compared with other testing methods that do not use the long-pass filter, the present invention uses a reference cell equipped with a long-pass filter as the basis for light source calibration when the current-limiting layer is the bottom cell layer, which can further reduce the testing error, is beneficial to improving the technical level of the industrial photovoltaic related technology, obtains accurate test results at a reasonable testing cost, and is beneficial to promoting the development of the photovoltaic device industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a schematic flow chart of the photovoltaic cell testing method according to an embodiment of the present invention;

[0019] Figure 2 It is an application schematic diagram of the photovoltaic cell testing process according to an embodiment of the present invention;

[0020] Figure 3 It is a spectral response curve diagram of many objects discussed in an embodiment of the present invention;

[0021] Figure 4 It is a transmittance schematic diagram of many band-pass filters according to an embodiment of the present invention; and

[0022] Figure 5 It is a transmittance schematic diagram of many long-pass filters according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It 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 to the present invention.

[0025] Please refer to Figure 1 As shown, an embodiment of a photovoltaic cell testing method provided by one aspect of the present invention may include: a dimming step S1 and a measurement step S2. The dimming step S1 can be used to finely adjust the light source as a basis for performing the measurement step S2. The following is an example to illustrate the implementation aspects of the embodiment of the photovoltaic cell testing method, but it is not limited thereto.

[0026] First of all, it should be noted that the embodiment of the photovoltaic cell testing method can use a testing device to perform a testing operation on a photovoltaic cell (such as a solar cell).

[0027] Please refer to Figure 2 As shown, the testing device E can be a photovoltaic cell testing device with functions such as external quantum efficiency (EQE) measurement, current density estimation, and data processing / input / output / storage. For example, the testing device E may include a xenon lamp component (such as a single xenon lamp) E1 and an LED component (such as an adjustable wavelength light emitting diode array) E2, used to generate a light source L that emits light toward an optical path as a simulated light source for irradiating a first reference cell RC1, a second reference cell RC2, and a cell under test T.

[0028] In this article, as Figure 1 shown, the first reference cell RC1 refers to a cell that is selected earlier during the light source fine adjustment process, and the second reference cell RC2 refers to a cell that is selected later during the light source fine adjustment process.

[0029] Optionally, as Figure 2As shown, the first reference cell RC1 and the second reference cell RC2 can be a standard reference cell respectively. For example, the first reference cell RC1 and the second reference cell RC2 each have a packaging window for receiving light source irradiation. Their structures are understandable to those with ordinary knowledge in the technical field and will not be elaborated here. In an embodiment, the packaging windows of the first reference cell RC1 and the second reference cell RC2 can also be configured with different specific wavelength filters. For example, the specific wavelength filter can be configured on a glass window to form the packaging window, or the packaging window can be formed by the specific wavelength filter, but not limited thereto. Thereby, the specific wavelength filter can be used to filter specific bands in the light source to accurately calibrate the light source, serving as a basis for subsequent battery measurement.

[0030] Optionally, as Figure 2 shown, the light source L can include a first light component L1 with a wavelength within the optical wavelength range of a light-emitting diode (LED) and a second light component L2 with an intensity within the light intensity range of a xenon lamp. For example, the second light component L2 can be generated by the xenon lamp component E1, and the first light component L1 can be generated by the LED component E2. For example, the LED component E2 can be finely adjusted to generate light with a specific wavelength from infrared light to ultraviolet light, such as visible light with a wavelength range of 390 to 780 nanometers (nm) and invisible light in other bands. The spectral response that the xenon lamp component E1 can generate is close to that of sunlight, such as a wavelength range of 300 to 1100 nanometers (nm). Thereby, the spectral response similar to sunlight can be simulated by using the xenon lamp component and the LED component.

[0031] Optionally, as Figure 2 shown, the battery under test T can be at least a tandem solar cell. The battery under test T can include a top cell layer (such as a top sub-cell of the tandem solar cell) and a bottom cell layer (such as a bottom sub-cell of the tandem solar cell). Thereby, the tandem solar cell can be tested. For example, the top cell layer and the bottom cell layer of the tandem solar cell can be tested separately to reduce test errors.

[0032] It should be understood that the tandem solar cell can be formed by stacking multiple sub-cells (which can be regarded as multiple series-connected cells). During the light irradiation process of these sub-cells, since the light reception amount of each sub-cell is not the same, the overall current of the tandem solar cell will be limited by the sub-cell with the smallest current density among these sub-cells. This sub-cell with the smallest current density determines a current-limiting layer. Taking the battery under test T as an example, one of the top cell layer and the bottom cell layer can be the current-limiting layer.

[0033] Optionally, as Figure 1 and Figure 2 shown, before the dimming step S1 of the photovoltaic cell testing method embodiment, a certain limit step S0 can also be performed to determine the current limiting layer of the battery under test T. For example, in the limit step S0, an external quantum efficiency of the top cell layer of the battery under test T can be measured by using the test device E; then, an external quantum efficiency of the bottom cell layer of the battery under test T can be measured by using the test device E; then, an integration operation of the external quantum efficiency of the top cell layer with respect to the standard solar spectrum response AM1.5G can be performed by using the corresponding software of the test device E to obtain a short-circuit current density of the top cell; then, an integration operation of the external quantum efficiency of the bottom cell layer with respect to the standard solar spectrum response AM1.5G can be performed by using the corresponding software of the test device E to obtain a short-circuit current density of the bottom cell; then, it can also be determined by using the corresponding software installed in the test device E whether the short-circuit current density of the top cell is less than the short-circuit current density of the bottom cell. If the determination is yes, the top cell layer is selected as the current limiting layer; if the determination is no, the bottom cell layer is selected as the current limiting layer. Thus, it can be stored in advance or known in real time that the current limiting layer of the battery under test is the top cell layer or the bottom cell layer, so as to be used as a basis for subsequent battery testing.

[0034] For example, as Figure 1 and Figure 2 shown, for the dimming step S1, the spectral response of the light source L can be adjusted by sequentially selecting the first reference cell RC1 and the second reference cell RC2; for the measuring step S2, an electrical curve of the battery under test T at a position in the light path of the light source L (such as at a specific distance below the light source L, but not limited thereto) can be measured.

[0035] It should be noted that, as Figure 3As shown, it is the spectral response curve diagram of many objects discussed in the embodiments of the present invention. Among them, C1, C2, C3, and C4 are the spectral response curves of the exemplary top cell layer, bottom cell layer, first reference cell, and second reference cell of the present invention respectively, and C5 is the spectral response curve of the existing silicon reference cell. These spectral response curves respectively represent the normalized quantum efficiency (Normalized QE) corresponding to different wavelengths. It should be noted that the encapsulation window of the conventional silicon reference cell uses quartz glass, and the wavelength range covered by its spectral response (SR) is from 300 to 1200 nanometers. If quartz glass is used as the encapsulation window of the reference cell, although it does not affect the wavelength range of the spectral response of the light source. However, if a reference cell with a quartz window and that has been calibrated is used as the basis for calibrating the light intensity of the xenon lamp, and then the current-voltage characteristic curve measurement operation of the battery under test is carried out, a relatively large spectral mismatch factor (mismatch factor, MMF) error will be generated, about greater than 5% (as Figure 3 shown in C5).

[0036] Please refer to Figure 2 and Figure 3 shown. It can be seen from the figure that the spectral response curve C5 of the existing silicon reference cell is very different from the spectral response curve C1 of the exemplary top cell layer and the spectral response curve C2 of the bottom cell layer of the present invention, which will lead to an excessive spectral mismatch factor error in the test results. In order to reduce the spectral mismatch factor error of the test results, it is still necessary to appropriately select the filters configured in the encapsulation windows of the first reference cell RC1 and the second reference cell RC2 that are used as reference cells. For example, according to the spectral response curves of the top cell layer and the bottom cell layer (as Figure 3 shown in C1 and C2), combined with the spectrum of the simulated light source and the standard solar spectrum (such as AM1.5G), based on the principle of minimizing the spectral mismatch factor error to select the filters, so as to select the spectral response curves of the appropriate first reference cell and the second reference cell (as Figure 3 shown in C3 and C4). For the reference cells (such as the first reference cell RC1 and the second reference cell RC2) selected through the appropriate selection process, the estimated spectral mismatch factor error can be less than 2%.

[0037] For example, as Figure 2As shown, in order to accommodate the differences between the current-limiting layer being the top cell layer or the bottom cell layer, the selected first reference cell RC1 is adaptively provided with different filters, and the selected second reference cell RC2 is also adaptively provided with different filters. For example, on the one hand, if the current-limiting layer is the top cell layer, the selected first reference cell RC1 can be provided with a band-pass filter and the selected second reference cell RC2 can be provided with a long-pass filter; on the other hand, if the current-limiting layer is the bottom cell layer, the selected first reference cell RC1 can be provided with the long-pass filter and the selected second reference cell RC2 can be provided with the band-pass filter. Among them, the band-pass filter refers to an optical filter having a specific light transmittance within a specific spectral band; the long-pass filter refers to an optical filter having a specific light transmittance within a longer spectral band.

[0038] Optionally, as Figure 1 and Figure 2 shown, in an embodiment, in the dimming step S1, the sequentially selecting the first reference cell RC1 and the second reference cell RC2 to calibrate the spectral response of the light source L includes the steps of: selecting the first reference cell RC1 and the second reference cell RC2 according to a current-limiting layer selected from a top cell layer and a bottom cell layer of the battery under test T. If the current-limiting layer is the top cell layer, the selected first reference cell RC1 is provided with the band-pass filter and the selected second reference cell RC2 is provided with the long-pass filter. If the current-limiting layer is the bottom cell layer, the selected first reference cell RC1 is provided with the long-pass filter and the selected second reference cell RC2 is provided with the band-pass filter. Thereby, different filters can be adaptively selected according to the difference between the current-limiting layer being the top cell layer or the bottom cell layer, which is beneficial to accurately calibrate the spectral response of the light source, so as to reduce the error in subsequent tests.

[0039] Optionally, the band-pass filter can be selected as a filter with an appearance close to colorless glass. For example, the light transmittance of the band-pass filter in the light transmission band of 330 to 720 nanometers is greater than 35% (such as 40%, 45%, 50%, 75%, 80%, 95%, etc.), so as to have an absorption effect in the infrared band. Among them, many transmittance curve characteristics that can be selected as the band-pass filter are shown in K1, K2, K3, and K4 in FIG. 4. For example, the band-pass filter can be selected as the band-pass filter of the KG series of SCHOTT, but not limited thereto. Thereby, the spectral response curve of the reference cell with the band-pass filter and the top cell layer can be made more adaptable.

[0040] Optionally, the long-pass filter may be a filter with an orange or red-black glass appearance. For example, in the light-transmitting band of the long-pass filter, the light transmittance of light with a wavelength above 700 nm (such as 800, 900, 1000, 1100, 1200 nm, etc.) is greater than 10% (such as 15%, 20%, 30%, 40%, 50%, 75%, 90%, etc.), so as to achieve the effect of high light transmittance in the infrared band and low light transmittance in the visible light band. Among the many transmittance curve characteristics that can be selected as the long-pass filter are those shown by O1, O2, O3, O4, O5, R1, R2, R3, R4, R5, and R6 in Figure 5. For example, the long-pass filter may be a long-pass filter of the RG or OG series of SCHOTT, but not limited thereto. Thereby, the spectral response curves of the reference cell with the band-pass filter and the bottom cell layer can be made more adaptable.

[0041] Optionally, as Figure 1 and Figure 2 shown, in an embodiment, in the dimming step S1, the sequential use of the first reference cell RC1 and the second reference cell RC2 to calibrate the spectral response of the light source L may further include the steps of: configuring the light source L to have a first light component L1 with a wavelength within the light wavelength range of the light-emitting diode; placing the first reference cell RC1 at the position in the light path of the light source L, and configuring the light source L to add a second light component L2 with an intensity within the light intensity range of the xenon lamp, so that the photoelectric characteristics of the first reference cell RC1 are equal to a first calibration characteristic. For example, the first reference cell RC1 is a calibrated reference cell, and the first calibration characteristic is a photocurrent value marked on a first calibration report of the first reference cell RC1 after calibration under a solar light intensity of 1000 W / m²; and placing the second reference cell RC2 at the position in the light path of the light source L, and adjusting the light intensity of the first light component L1 so that the photoelectric characteristics of the second reference cell RC2 are greater than a second calibration characteristic. For example, the second reference cell RC2 is a calibrated reference cell, and the second calibration characteristic is a photocurrent value marked on a second calibration report of the second reference cell RC2 after calibration under a solar light intensity of 1000 W / m². Thereby, reference cells with different filters can be selected according to different current-limiting layer characteristics as the basis for adjusting different light components, which is beneficial to accurately calibrating the spectral response of the light source, so as to reduce the error in the subsequent measurement of the battery under test.

[0042] Optionally, as Figure 1 and Figure 2As shown, in one embodiment, the wavelength of the first light component when the current-limiting layer is the top cell layer is different from the wavelength of the first light component when the current-limiting layer is the bottom cell layer. For example, the wavelength of the first light component when the current-limiting layer is the top cell layer is within an infrared light wavelength range, but not limited thereto. Thereby, according to the characteristics of different current-limiting layers, light within an appropriate light wave range can be pre-adjusted as the basis for calibrating the light source.

[0043] Optionally, as Figure 1 and Figure 2 shown, in one embodiment, in the dimming step S1, after making the optoelectronic characteristics generated by the second reference cell RC2 greater than the second calibration characteristics, the following steps may further be included: measuring the optical characteristics of the light source L, where the optical characteristics include the spectral response of the first light component L1 and the spectral response of the second light component L2. For example, the spectral response of the light source L is measured using a spectrometer, but not limited thereto. Thereby, the spectral response of the first light component and the spectral response of the second light component can be stored as the test parameters for subsequent same-type battery components to be tested, and can be used as the basis for data analysis of related processes.

[0044] The following examples illustrate the photovoltaic cell test scenarios under different current-limiting layers, aiming to enable relevant personnel to better understand the above embodiments of the present invention, and are not intended to limit the present invention.

[0045] On the one hand, as Figure 1 and Figure 2As shown, after learning about the current-limiting layer of the battery T to be measured (for example, by performing the limit-setting step S0 in advance), if the current-limiting layer of the battery T to be measured is the "top cell layer", the dimming step S1 can be performed to carry out the light source intensity calibration process. First, the LED component E2 can be turned on to generate the first light component L1 (for example, with a wavelength in the infrared light band); then, a reference battery that has been calibrated and whose calibration report can be traced (for example, the first reference battery RC1 with a "band-pass filter") can be placed under the light source L (with only the first light component L1), and the xenon lamp component E1 can be turned on and the intensity of the second light component L2 can be adjusted so that the photocurrent value generated by the first reference battery RC1 with a "band-pass filter" is equal to the first calibration characteristic (for example, the photocurrent value of the first reference battery RC1 after calibration and marked on the first calibration report at a solar light intensity of 1000 watts per square meter); then, a reference battery that has been calibrated and whose calibration report can be traced (such as the second reference battery RC2 with a "long-pass filter") can be placed under the light source L (mixing the first light component L1 and the second light component L2), and the intensity of the first light component L1 generated by the LED component E2 can be appropriately adjusted so that the photocurrent value generated by the second reference battery RC2 with a "long-pass filter" is greater than the second calibration characteristic (for example, the photocurrent value of the second reference battery RC2 after calibration and marked on the second calibration report at a solar light intensity of 1000 watts per square meter); then, the spectral response of the light source L (mixing the first light component L1 and the second light component L2) can be measured using a spectrometer; then, the measurement step S2 can be performed, and the battery T to be measured can be placed under the light source L (mixing the first light component L1 and the second light component L2) to perform a current-voltage characteristic curve measurement operation on the battery T to be measured. After obtaining a test result, the test process of the above method embodiment can be completed.

[0046] On the other hand, as Figure 1 and Figure 2As shown, after learning the current-limiting layer of the battery T to be measured (for example, by performing the above-mentioned current-limiting step S0 in advance), if the current-limiting layer of the battery T to be measured is the "bottom battery layer", the dimming step S1 can be performed. First, a light source intensity calibration process is carried out. The wavelength-related setting of the first light component L1 can be changed, and the LED component E2 can be turned on. Then, the reference battery (for example, the first reference battery RC1 with a "long-pass filter") can be placed under the light source L (only having the first light component L1). Additionally, the xenon lamp component E1 can be turned on and the intensity of the second light component L2 can be adjusted so that the photocurrent value generated by the first reference battery RC1 with a "long-pass filter" is equal to the first calibration characteristic (for example, the photocurrent value of the first reference battery RC1 marked on the first calibration report under the sunlight intensity of 1000 watts per square meter after being calibrated). Next, the reference battery (such as the second reference battery RC2 with a "band-pass filter") can be placed under the light source L (mixing the first light component L1 and the second light component L2), and the intensity of the first light component L1 generated by the LED component E2 can be appropriately adjusted so that the photocurrent value generated by the second reference battery RC2 with a "band-pass filter" is greater than the second calibration characteristic (for example, the photocurrent value of the second reference battery RC2 marked on the second calibration report under the sunlight intensity of 1000 watts per square meter after being calibrated). Then, the spectral response of the light source L (mixing the first light component L1 and the second light component L2) can be measured using a spectrometer. Next, the measurement step S2 can be carried out. The battery T to be measured can be placed under the light source L (mixing the first light component L1 and the second light component L2), and a current-voltage characteristic curve measurement operation of the battery T to be measured can be performed. After obtaining a test result, the test process of the above method embodiment can be completed.

[0047] It should be noted that if the current-limiting layer is the "bottom battery layer" and the test is carried out by other methods than the above-mentioned embodiments of the present invention, for example, using a reference battery with a quartz filter for the light source intensity calibration process, the test result will have a very large error. On the other hand, if the current-limiting layer is the "bottom battery layer" and only a reference battery with a non-quartz filter is used but the reference battery with a long-pass filter adopted by the present invention is not used, the test result will also have a very large error. Therefore, if the current-limiting layer is the "bottom battery layer", using the reference battery with a long-pass filter for the light source intensity calibration process in the above-mentioned embodiments of the present invention can obtain a test result with relatively small error and high accuracy.

[0048] As described above, in the embodiment of the photovoltaic cell testing method of the present invention, according to the different current-limiting layers of the battery to be tested, a reference cell with the band-pass filter or long-pass filter can be sequentially selected as the basis for calibrating the spectral response of the light source. After testing the electrical characteristics of the battery to be tested with the spectral response of the calibrated light source, a test result with a low spectral response mismatch factor error can be obtained. Compared with other testing methods that do not use the long-pass filter, the present invention uses a reference cell with a long-pass filter as the basis for light source calibration when the current-limiting layer is the bottom cell layer, which can further reduce the testing error, is beneficial to improving the technical level of the industrial photovoltaic related technology, obtaining accurate test results at a reasonable test cost, and is beneficial to promoting the development of the photovoltaic device industry.

[0049] The embodiments of the present invention have been described in detail above. Specific examples are used herein to illustrate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present invention; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing a photovoltaic cell, characterized in that, Including steps: Selecting a first reference cell and a second reference cell in sequence to calibrate the spectral response of a light source, one of the selected first reference cell and second reference cell has a band-pass filter, and the other of the selected first reference cell and second reference cell has a long-pass filter, the light transmittance of the band-pass filter for light with a wavelength range of 330 to 720 nanometers is greater than 35%, and the light transmittance of the long-pass filter for light with a wavelength of more than 700 nanometers is greater than 10%; and Measuring an electrical property curve of a battery under test at a position in an optical path of the light source; The sequentially selecting the first reference cell and the second reference cell to calibrate the spectral response of the light source includes steps: Selecting the first reference cell and the second reference cell according to a current-limiting layer selected from a top cell layer and a bottom cell layer of the battery under test. If the current-limiting layer is the top cell layer, the selected first reference cell has the band-pass filter and the selected second reference cell has the long-pass filter. If the current-limiting layer is the bottom cell layer, the selected first reference cell has the long-pass filter and the selected second reference cell has the band-pass filter; Configuring the light source to have a first light component with a wavelength within the optical wavelength range of a light-emitting diode; Placing the first reference cell at the position in the optical path of the light source, and configuring the light source to add a second light component with an intensity within the optical intensity range of a xenon lamp, so that the optoelectronic characteristics of the first reference cell are equal to a first calibration characteristic; and Placing the second reference cell at the position in the optical path of the light source, and adjusting the light intensity of the first light component so that the optoelectronic characteristics of the second reference cell are greater than a second calibration characteristic; The first reference cell and the second reference cell are respectively a calibrated reference cell. The first calibration characteristic is a photocurrent value marked on a first calibration report of the first reference cell after calibration under a solar light intensity of 1000 watts per square meter. The second calibration characteristic is a photocurrent value marked on a second calibration report of the second reference cell after calibration under a solar light intensity of 1000 watts per square meter.

2. The photovoltaic cell testing method according to claim 1, characterized in that The wavelength of the first light component when the current-limiting layer is the top cell layer is different from the wavelength of the first light component when the current-limiting layer is the bottom cell layer.

3. The photovoltaic cell testing method according to claim 2, wherein The wavelength of the first light component when the current-limiting layer is the top cell layer is within an infrared wavelength range.

4. The photovoltaic cell testing method according to claim 1, wherein, After making the optoelectronic characteristics generated by the second reference cell greater than the second calibration characteristic, the photovoltaic cell testing method further includes steps: measuring the optical characteristics of the light source, and the optical characteristics include the spectral response of the first light component and the spectral response of the second light component.

5. The photovoltaic cell testing method according to claim 1, characterized in that, It further includes the steps of: measuring an external quantum efficiency of the top cell layer of the battery to be measured; measuring an external quantum efficiency of the bottom cell layer of the battery to be measured; performing an integration operation on the external quantum efficiency of the top cell layer with respect to a standard solar spectral response AM1.5G to obtain a short-circuit current density of the top cell; performing an integration operation on the external quantum efficiency of the bottom cell layer with respect to the standard solar spectral response AM1.5G to obtain a short-circuit current density of the bottom cell; determining whether the short-circuit current density of the top cell is less than the short-circuit current density of the bottom cell, and if the determination is yes, selecting the top cell layer as the current-limiting layer, and if the determination is no, selecting the bottom cell layer as the current-limiting layer.

6. The photovoltaic cell testing method according to claim 1, wherein The first reference cell and the second reference cell each have a packaging window, and the packaging window is configured to have the long-pass filter or the band-pass filter.

7. The photovoltaic cell testing method according to claim 1, wherein The battery to be measured is a tandem solar cell.

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