Methods, systems, apparatuses, devices, and media of testing solar cells

Abstract

The application discloses a solar cell testing method, system, device, equipment and medium. The solar cell includes a sub-cell, and the testing method includes: applying bias light corresponding to a characteristic absorption light wavelength of the sub-cell to the solar cell to obtain first photovoltaic characteristic data of the sub-cell under the bias light; applying specified test light and bias light corresponding to the characteristic absorption light wavelength of the sub-cell to the solar cell to obtain a target short-circuit current density of the sub-cell; and obtaining second photovoltaic characteristic data of the sub-cell under the specified test light based on the first photovoltaic characteristic data and the target short-circuit current density. Thus, the testing accuracy of the solar cell is improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor optoelectronic and optoelectronic component testing technology, and in particular to a testing method, system, apparatus, equipment, and dielectric for solar cells. Background Technology

[0002] As a promising new photovoltaic technology, perovskite solar cells have made remarkable progress. However, the photoelectric conversion efficiency of single-junction perovskite solar cells is gradually approaching its energy conversion limit, making it extremely difficult to further improve their efficiency. Therefore, fabricating multi-junction solar cells is one of the simplest methods to further improve the efficiency of perovskite solar cells. Multi-junction solar cells consist of cells with different bandgap absorption layers. By differentially absorbing a wider range of wavelengths of sunlight, the device efficiency can be further improved.

[0003] Multijunction solar cells typically have only two electrodes, with no electrodes leading out between the sub-cells. When testing the photovoltaic characteristic data of the sub-cells, the influence of reverse bias voltage can lead to inaccurate testing. If additional related devices (such as resistors) are connected to the solar cell to reduce the reverse bias voltage, the additional devices will also affect the measurement results, resulting in inaccurate measurements. Summary of the Invention

[0004] In view of the above problems, this application provides a testing method, system, apparatus, device, and dielectric for solar cells, which can effectively solve the problem that the existing technology cannot quickly and accurately test the voltage characteristic data of solar cells.

[0005] On one hand, this application provides a testing method for a solar cell, the solar cell including a sub-cell, the method comprising: applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain first photovoltaic characteristic data of the sub-cell under the bias light; applying specified test light and bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain a target short-circuit current density of the sub-cell; and obtaining second photovoltaic characteristic data of the sub-cell under the specified test light based on the first photovoltaic characteristic data and the target short-circuit current density.

[0006] According to the embodiments of this application, the first photovoltaic characteristic data of the sub-cell under the bias light is obtained by applying bias light to the solar cell, the target short-circuit current density of the sub-cell is obtained by applying specified test light and bias light, and the second photovoltaic characteristic data of the sub-cell under the specified test light is obtained based on the first photovoltaic characteristic data and the target short-circuit current density. There is no need to add additional devices (such as resistors) to connect to the solar cell to reduce the reverse bias voltage, avoiding the influence of additional devices on the measurement results and improving the test accuracy.

[0007] In some embodiments, the first photovoltaic characteristic data includes the relationship data between the open-circuit voltage and short-circuit current density of the sub-cell under bias light; based on the first photovoltaic characteristic data and the target short-circuit current density, the second photovoltaic characteristic data of the sub-cell under specified test light is obtained, including: according to a first preset relationship, based on the target short-circuit current density and the relationship data between the open-circuit voltage and the short-circuit current density of the sub-cell, the second photovoltaic characteristic data includes at least one of the following parameters under specified test light: the open-circuit voltage of the sub-cell, the short-circuit current density of the sub-cell, the fill factor of the sub-cell, the photoelectric conversion efficiency of the sub-cell, and the contribution value of the photoelectric conversion efficiency of the sub-cell.

[0008] According to the embodiments of this application, by using a first preset relationship, data fitting can be performed on the target short-circuit current density and the relationship data between the sub-cell open-circuit voltage and the sub-cell short-circuit current density to obtain second photovoltaic characteristic data, thereby improving testing efficiency and convenience.

[0009] In some embodiments, the first photovoltaic characteristic data includes the sub-cell ideal performance factor under bias light; the method further includes: acquiring the relationship data between the overall open-circuit voltage and the overall short-circuit current density of the solar cell under specified test light; and obtaining the corrected second photovoltaic characteristic data based on the sub-cell ideal performance factor, the relationship data between the overall open-circuit voltage and the overall short-circuit current density, and the second photovoltaic characteristic data.

[0010] According to an embodiment of this application, the second photovoltaic characteristic data is ideal data. In order to further improve its accuracy, based on the relationship data of the sub-cell ideal performance factor, the overall open-circuit voltage and the overall short-circuit current density, and the second photovoltaic characteristic data, a corrected second photovoltaic characteristic data is obtained to improve the test accuracy.

[0011] In some embodiments, based on the relationship data of the sub-cell ideal performance factor, the overall open-circuit voltage and the overall short-circuit current density, and the second photovoltaic characteristic data, the corrected second photovoltaic characteristic data is obtained, including: according to a second preset relationship, based on the sub-cell ideal performance factor and the second photovoltaic characteristic data, obtaining the sub-cell photogenerated current density and the sub-cell saturated dark current density; according to a third preset relationship, based on the relationship data of the sub-cell photogenerated current density, the sub-cell saturated dark current density, the overall open-circuit voltage and the overall short-circuit current density, obtaining photovoltaic characteristic fitting data; and based on the photovoltaic characteristic fitting data, obtaining the corrected second photovoltaic characteristic data.

[0012] According to an embodiment of this application, the ideal performance factor of the battery and the second photovoltaic characteristic data are fitted based on the second preset relationship to obtain the photocurrent density and the saturation dark current density of the sub-cell. Then, the relationship data of the photocurrent density, the saturation dark current density, the overall open-circuit voltage and the overall short-circuit current density of the sub-cell are further fitted based on the third preset relationship to obtain photovoltaic characteristic fitting data, thereby improving the data fitting effect. Finally, the corrected second photovoltaic characteristic data are obtained based on the photovoltaic characteristic fitting data.

[0013] In some embodiments, the photovoltaic feature fitting data includes the sub-cell resistance; based on the photovoltaic feature fitting data, the corrected second photovoltaic feature data is obtained, including: according to a fourth preset relationship, the corrected second photovoltaic feature data is obtained based on the sub-cell resistance, the sub-cell photogenerated current density, the sub-cell saturated dark current density, and the sub-cell ideal performance factor.

[0014] According to the embodiments of this application, the sub-cell resistance, sub-cell photogenerated current density, sub-cell saturated dark current density, and sub-cell ideal performance factor are processed based on the fourth preset relationship to obtain the corrected second photovoltaic characteristic data, thereby improving the accuracy and convenience of testing.

[0015] In some embodiments, the sub-cell includes a first sub-cell and a second sub-cell; applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain first photovoltaic characteristic data of the sub-cell under bias light includes: applying bias light corresponding to the characteristic absorption wavelength of the first sub-cell to the solar cell to obtain first photovoltaic characteristic data of the first sub-cell under bias light; applying bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell to obtain first photovoltaic characteristic data of the second sub-cell under bias light.

[0016] According to the embodiments of this application, bias light corresponding to the characteristic absorption wavelength is applied to each sub-cell to obtain the first photovoltaic characteristic data of each sub-cell, and the testing method is simple and convenient.

[0017] In some embodiments, the first sub-cell includes a narrow-bandgap sub-cell, and the second sub-cell includes a wide-bandgap sub-cell, wherein the characteristic absorption wavelength of the narrow-bandgap sub-cell is greater than the characteristic absorption wavelength of the wide-bandgap sub-cell. Applying bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell to obtain first photovoltaic characteristic data of the second sub-cell under bias light includes: applying bias light corresponding to the characteristic absorption wavelength of the wide-bandgap sub-cell to the solar cell to obtain the open-circuit voltage and short-circuit current density of the wide-bandgap sub-cell under bias light; correcting the open-circuit voltage of the wide-bandgap sub-cell based on the reference open-circuit voltage of the narrow-bandgap sub-cell to obtain the corrected open-circuit voltage of the wide-bandgap sub-cell; and obtaining the first photovoltaic characteristic data of the wide-bandgap sub-cell under bias light based on the corrected open-circuit voltage and short-circuit current density of the wide-bandgap sub-cell.

[0018] In some embodiments, the reference open-circuit voltage of the narrow bandgap cell is obtained by applying bias light corresponding to the characteristic absorption wavelength of the narrow bandgap cell to the solar cell, obtaining data on the relationship between the open-circuit voltage of the narrow bandgap cell and the irradiance of the bias light; and determining the open-circuit voltage corresponding to a specified irradiance intensity as the reference open-circuit voltage of the narrow bandgap cell.

[0019] According to embodiments of this application, for narrow-bandgap solar cells and wide-bandgap solar cells, in order to solve the problem that when bias light corresponding to the characteristic absorption wavelength of a wide-bandgap solar cell is applied to a solar cell, the narrow-bandgap solar cell absorbs a small portion of the bias light, resulting in inaccurate first photovoltaic characteristic data of the wide-bandgap solar cell under bias light, this application corrects the open-circuit voltage of the wide-bandgap solar cell based on the reference open-circuit voltage of the narrow-bandgap solar cell, thereby improving the accuracy of the first photovoltaic characteristic data of the wide-bandgap solar cell under bias light.

[0020] In some embodiments, a sub-cell includes multiple sub-cells; applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to a solar cell to obtain a target short-circuit current density of the sub-cell includes: applying a specified test light to the solar cell and applying a first bias light corresponding to the characteristic absorption wavelength of each sub-cell to the solar cell respectively; determining a first sub-cell from the multiple sub-cells based on first variation data of the first short-circuit current density of the solar cell changing with the irradiance of the first bias light; applying a specified test light to the solar cell and applying a second bias light corresponding to the characteristic absorption wavelength of the first sub-cell to the solar cell; and determining the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell based on second variation data of the second short-circuit current density of the solar cell changing with the irradiance of the second bias light.

[0021] According to embodiments of this application, when a solar cell is under specified test light conditions, by applying additional bias light corresponding to the characteristic absorption wavelength of the sub-cell and by changing the irradiance of the bias light, the current-limiting sub-cells of the solar cell can be quickly identified and the target short-circuit current density of each sub-cell can be accurately measured. This method is efficient, simple, and low-cost. The bias light is set according to the characteristic absorption wavelength, and the irradiance conditions of the bias light can be changed for testing. The test is conducted using bias light, and the test conditions are provided by the bias light. The bias light can be adjusted for the test equipment, which has low requirements for the test equipment and the adjustment of the bias light is easy to implement, thereby improving the test effect, reducing the difficulty of the test, and reducing the test cost.

[0022] In some embodiments, determining the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell based on second variation data of the second short-circuit current density of the solar cell changing with the irradiation intensity of the second bias light includes: determining the second short-circuit current density of the solar cell corresponding to the target irradiation intensity based on the second variation data, and using it as the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell.

[0023] In some embodiments, the second change data includes first change trend data and second change trend data, wherein the change trend of the first change trend data is greater than the change trend of the second change trend data; determining the second short-circuit current density of the solar cell corresponding to the target irradiance based on the second change data, as the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell, includes: determining the second short-circuit current density of the solar cell corresponding to the first target irradiance based on the first change trend data, as the target short-circuit current density of the first sub-cell; and / or determining the second short-circuit current density of the solar cell corresponding to the second target irradiance based on the second change trend data, as the target short-circuit current density of the second sub-cell.

[0024] According to the embodiments of this application, second change data can be acquired by applying a second bias light once. The second change data includes data with different change trends. The target short-circuit current density of different sub-cells is determined based on the data with different change trends. The target short-circuit current density of two sub-cells can be acquired by applying a second bias light once, which improves the test speed. Furthermore, the target short-circuit current density of the first sub-cell and the target short-circuit current density of the second sub-cell are determined based on the first target irradiance and the second target irradiance, respectively, which improves the test accuracy of short-circuit current density.

[0025] In some embodiments, the method further includes obtaining the second change data by: acquiring a plurality of test data points, wherein each test data point includes irradiance and the corresponding second short-circuit current density of the solar cell; and performing data fitting based on the plurality of test data points to obtain the second change data.

[0026] According to the embodiments of this application, the second change data is obtained by fitting multiple test data points, which can improve the testing speed and simplify the testing process by collecting a smaller amount of test data.

[0027] In some embodiments, the sub-cell includes n sub-cells, n≥2; applying a first bias light corresponding to the characteristic absorption wavelength of each sub-cell to the solar cell includes: applying a first bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell to obtain n first change data corresponding one-to-one with the n sub-cells, 1≤i≤n; determining a first sub-cell from the multiple sub-cells based on the first change data of the first short-circuit current density of the solar cell changing with the irradiance of the first bias light includes: determining a target first change data whose data change rate satisfies a first preset rate condition from the n first change data; and determining the sub-cell corresponding to the target first change data as the first sub-cell.

[0028] According to an embodiment of this application, when determining the first sub-cell (current-limited sub-cell) from multiple sub-cells, multiple first change data are obtained by applying a first bias light corresponding to the characteristic absorption wavelength of each sub-cell, and the sub-cell corresponding to the target first change data whose data change rate satisfies a first preset rate condition (e.g., the fastest change rate) is determined as the first sub-cell (current-limited sub-cell), thereby improving the testing accuracy and speed of the current-limited sub-cell.

[0029] In some embodiments, the first sub-cell is one of n sub-cells; the method further includes: for the n-1 sub-cells other than the first sub-cell, applying third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell, and collecting the third short-circuit current density of the solar cell, so as to obtain n-1 third change data corresponding one-to-one with the n-1 sub-cells based on the third short-circuit current density of the solar cell, 1≤i≤n-1; determining the target third change data whose data change rate satisfies the second preset rate condition from the n-1 third change data; and determining the sub-cell corresponding to the target third change data as the second sub-cell.

[0030] According to an embodiment of this application, when determining the second sub-cell (current-limited sub-cell) from multiple sub-cells, multiple third change data are obtained by applying a third bias light corresponding to the characteristic absorption wavelength of each sub-cell. The sub-cell corresponding to the target third change data whose data change rate satisfies a second preset rate condition (e.g., the fastest change rate) is determined as the second sub-cell (current-limited sub-cell), thereby improving the testing accuracy and speed of the current-limited sub-cell.

[0031] In some embodiments, for n-1 sub-cells other than the first sub-cell, applying a third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell includes: applying a third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell based on applying a second bias light whose irradiance intensity meets a preset threshold condition, wherein the irradiance intensity meeting the preset threshold condition includes the irradiance intensity being a preset multiple of a specific irradiance intensity, and the specific irradiance intensity being the irradiance intensity corresponding to the degree to which the change in the second short-circuit current density of the solar cell with the irradiance intensity of the second bias light is less than or equal to a preset degree.

[0032] According to embodiments of this application, on one hand, by increasing the specific irradiance of the second bias light to a preset multiple (e.g., twice), the limitation of the first sub-cell on the maximum short-circuit current density of the solar cell can be overcome, so that the first sub-cell is no longer a current-limiting sub-cell. This allows for the identification of the current-limiting second sub-cell among the other sub-cells of the solar cell, enabling rapid identification of the current-limiting sub-cell and accurate measurement of the target short-circuit current density of each sub-cell. On the other hand, by increasing the specific irradiance of the second bias light to more than twice but less than twice, not only can the limitation of the first sub-cell on the maximum short-circuit current density of the solar cell be overcome, but the influence of the bias light corresponding to the characteristic absorption wavelength of the first sub-cell on the second sub-cell can also be reduced, further improving the accuracy of the test results.

[0033] In some embodiments, when n≥3, the method further includes: applying a specified test light to the solar cell, applying a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell, and acquiring the fourth short-circuit current density of the solar cell; and determining the target short-circuit current density of the third sub-cell based on the fourth variation data of the fourth short-circuit current density of the solar cell as a function of the irradiance of the fourth bias light.

[0034] According to embodiments of this application, under specified test light, by applying additional bias light corresponding to the characteristic absorption wavelength of the sub-cell, and adjusting the irradiance of the bias light, the current-limiting sub-cells of the solar cell can be quickly identified, and the target short-circuit current density of each sub-cell can be accurately measured. Following this method, when there are multiple sub-cells in the solar cell, the target short-circuit current density of each sub-cell can also be accurately and efficiently determined. Furthermore, the accuracy of the test results can be improved by adjusting the irradiance of the bias light. This method is efficient, simple, and accurate, and can effectively improve the efficiency of identifying process problems in solar cells during actual production.

[0035] In some embodiments, applying a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell includes: applying a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell based on applying a second bias light whose irradiance intensity meets a preset threshold condition, wherein the irradiance intensity meeting the preset threshold condition includes the irradiance intensity being a preset multiple of a specific irradiance intensity, and the specific irradiance intensity being the irradiance intensity corresponding to the degree to which the change in the second short-circuit current density of the solar cell with the irradiance intensity of the second bias light is less than or equal to a preset degree.

[0036] On the other hand, this application provides a testing method for a solar cell, the solar cell including a sub-cell, the method comprising: acquiring first photovoltaic characteristic data of the sub-cell under bias light, wherein the first photovoltaic characteristic data is obtained by applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell; acquiring a target short-circuit current density of the sub-cell, wherein the target short-circuit current density is obtained by applying a specified test light and bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell; and obtaining second photovoltaic characteristic data of the sub-cell under specified test light based on the first photovoltaic characteristic data and the target short-circuit current density.

[0037] On the other hand, this application provides a solar cell testing system, the system comprising: a solar cell, the solar cell including sub-cells; a test light device configured to apply specified test light to the solar cell based on a first control command; a bias light device configured to apply bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell based on a second control command; a data acquisition device configured to acquire first photovoltaic characteristic data of the sub-cell under the bias light when the bias light corresponding to the characteristic absorption wavelength of the sub-cell is applied to the solar cell, and to acquire a target short-circuit current density of the sub-cell when the specified test light and the bias light corresponding to the characteristic absorption wavelength of the sub-cell are applied to the solar cell; and a data processing device configured to send a first control command to the test light device, send a second control command to the bias light device, acquire the first photovoltaic characteristic data and the target short-circuit current density from the data acquisition device, and obtain second photovoltaic characteristic data of the sub-cell under the specified test light based on the first photovoltaic characteristic data and the target short-circuit current density.

[0038] On the other hand, this application provides a testing apparatus for a solar cell, the solar cell including a sub-cell, the apparatus including: a first acquisition module for acquiring first photovoltaic characteristic data of the sub-cell under bias light, wherein the first photovoltaic characteristic data is obtained by applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell; a second acquisition module for acquiring a target short-circuit current density of the sub-cell, wherein the target short-circuit current density is obtained by applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell; and a third acquisition module for obtaining second photovoltaic characteristic data of the sub-cell under specified test light based on the first photovoltaic characteristic data and the target short-circuit current density.

[0039] On the other hand, this application provides an electronic device including a memory and a processor, wherein the memory stores a computer program, characterized in that the processor executes the computer program to implement the steps of the method of any of the above embodiments.

[0040] On the other hand, this application provides a computer-readable storage medium in which a computer program, when executed by a processor, implements the steps of any of the above-described embodiments.

[0041] On the other hand, this application provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the method described in any of the above embodiments.

[0042] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0044] Figure 1 A schematic diagram of photovoltaic characteristic curves provided for embodiments of this application;

[0045] Figure 2 A schematic flowchart illustrating a testing method for a solar cell provided in this application embodiment;

[0046] Figure 3 A schematic diagram of the overall photovoltaic characteristic curve of a solar cell under specified test light provided for an embodiment of this application;

[0047] Figure 4 This is a schematic diagram illustrating the application of 750nm LED bias light to a solar cell according to an embodiment of this application.

[0048] Figure 5 This is a schematic diagram illustrating the relationship between the open-circuit voltage of the narrow-bandgap subcell and the irradiance of a 750nm LED according to an embodiment of this application.

[0049] Figure 6 This is a schematic diagram illustrating the application of bias light corresponding to multiple sub-cells to a solar cell in accordance with an embodiment of this application.

[0050] Figure 7 This is a schematic diagram illustrating the dependence of open-circuit voltage and short-circuit current density of wide and narrow bandgap sub-cells under different irradiation intensities according to embodiments of this application.

[0051] Figure 8 This is a schematic diagram illustrating the application of specified test light and bias light to a solar cell according to an embodiment of this application.

[0052] Figure 9 A schematic diagram illustrating the determination of the target short-circuit current density of the sub-cell in an embodiment of this application;

[0053] Figure 10 A schematic diagram illustrating the determination of the ideal photovoltaic characteristic curve of the sub-cell under specified test light for embodiments of this application;

[0054] Figure 11 This is a schematic diagram of the photovoltaic characteristic curve fitting of the solar cell and sub-cell according to the embodiments of this application;

[0055] Figure 12 This is a schematic diagram of the photovoltaic characteristic curve fitting of the modified sub-cell according to the embodiments of this application;

[0056] Figure 13 A schematic diagram of the process for testing the target short-circuit current density of a sub-battery provided in an embodiment of this application;

[0057] Figure 14 A schematic diagram illustrating the determination of the first sub-cell of a solar cell according to an embodiment of this application;

[0058] Figure 15 A schematic diagram of the fitting curve of the relationship between the first bias light of the 450nm LED and the short-circuit current density of the solar cell when determining the target short-circuit current density of the first and second sub-cells of the solar cell, as provided in an embodiment of this application.

[0059] Figure 16 A schematic diagram of the fitting curve of the relationship between the second bias light of a 750nm LED and the short-circuit current density of a solar cell provided in an embodiment of this application;

[0060] Figure 17 A schematic diagram illustrating the determination of the target short-circuit current density of the third sub-cell of a solar cell, provided as an embodiment of this application;

[0061] Figure 18 A schematic diagram of the fitting curve of the relationship between 450nm LED bias light and solar cell short-circuit current density when determining the target short-circuit current density of the third sub-cell of a solar cell, provided for an embodiment of this application.

[0062] Figure 19 A schematic flowchart illustrating a testing method for a solar cell provided in this application embodiment;

[0063] Figure 20 A schematic diagram of a solar cell testing system provided for an embodiment of this application;

[0064] Figure 21 A schematic diagram of a solar cell testing apparatus provided for an embodiment of this application;

[0065] Figure 22 A block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0066] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0068] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0069] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0070] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0071] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0072] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0073] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0074] Stacked solar cells can be arranged in various ways, including two-terminal, three-terminal, and four-terminal structures. Among them, two-terminal stacked solar cells refer to the direct fabrication of a bottom narrow-bandgap sub-cell on a top wide-bandgap sub-cell, with the two sub-cells connected in series through a tunnel junction or composite layer. This structure requires only one transparent metal oxide electrode, which can effectively reduce parasitic absorption and lower costs, and is considered to be the mainstream technology route in the future photovoltaic field.

[0075] Because two-terminal tandem solar cells have only two electrodes and no electrodes connecting the two sub-cells, it is impossible to test individual sub-cells separately. For example, it is impossible to test the contribution of each sub-cell to the overall efficiency of the tandem solar cell. Furthermore, there is a lack of effective tools for characterizing the sub-cells of two-terminal tandem solar cells. Especially in actual production environments, when two-terminal tandem solar cells exhibit efficiency anomalies, it is difficult to quickly decouple the process problems existing in individual sub-cells. Therefore, there is an urgent need to develop a testing method that can decouple the performance of sub-cells in two-terminal tandem solar cells. It is understood that the testing method of this application is also applicable to three-terminal or four-terminal tandem solar cell structures with only two electrodes and no electrodes connecting multiple sub-cells.

[0076] Before describing the testing methods of this application, relevant concepts will be introduced.

[0077] Current-limited subcell: refers to the subcell in a solar cell with the lowest short-circuit current density under a certain irradiation condition.

[0078] Characteristic absorption light: Different semiconductor materials have different characteristic band gaps, which can selectively absorb light of different wavelengths in the spectrum. For example, for wide band gap perovskite, its band gap is 1.85 eV, and it can only absorb light with wavelengths less than 670 nm. Therefore, 450 nm light can be selected as its characteristic absorption light.

[0079] Photovoltaic characteristic curve (IV curve) and photovoltaic characteristic data (parameters), Figure 1 An example photovoltaic characteristic curve (IV curve representing the relationship between current and voltage) is shown. The meaning of the photovoltaic characteristic data is as follows:

[0080] Open circuit voltage (V) OC ): The voltage of a solar cell under open-circuit conditions (0 current) when illuminated, expressed in volts (V).

[0081] Short-circuit current density (J) SC ): The current density of a solar cell under short-circuit conditions (voltage is 0) when illuminated, expressed in mA / cm². -2 ;

[0082] Fill factor (FF): An important indicator for measuring the output characteristics of a solar cell, FF = (Jmax × Vmax) / (J SC *V OC ), J max and V max These represent the maximum output power (P) max The corresponding current density and voltage value;

[0083] Photovoltaic conversion efficiency (PCE): The most important indicator for evaluating the quality of solar cells. It measures the ability of a solar cell to convert light into electricity. PCE = (J / L) SC *V OC *FF) / Pin, where Pin is the incident light power.

[0084] Ideal factor (n) id ): This refers to the ideal diode factor, a metric that measures how well a diode follows the ideal diode equation. Solar cell open-circuit voltage (V) OC )and It is directly proportional, where K is the Boltzmann constant, T is the thermodynamic temperature, q is the elementary charge, and P is the molecular weight. light The intensity of light received by the solar cell.

[0085] Shockley equations:

[0086]

[0087] The Shockley equation is a formula describing the exponential relationship between current and voltage in a diode under conduction conditions, where J is the diode's current density. ph Let J0 be the photogenerated current density, J0 be the saturated dark current density, q be the elementary charge, V be the voltage, and n be the voltage. id Here, K is the ideality factor, K is the Boltzmann constant, and T is the thermodynamic temperature.

[0088] Kirchhoff's laws are the fundamental laws governing voltage and current in a circuit. In this application, they can be simply understood as follows: the current density of a multijunction solar cell depends on the current density of the sub-cell with the minimum current density (i.e., the current-limited sub-cell).

[0089] Figure 2This is a flowchart illustrating a testing method for a solar cell provided in an embodiment of this application.

[0090] like Figure 2 As shown, this application provides a testing method 200 for a solar cell, the solar cell including a sub-cell, the method including steps S210-S230.

[0091] Step S210: Apply bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain the first photovoltaic characteristic data of the sub-cell under bias light.

[0092] Step S220: Apply bias light corresponding to the specified test light and the characteristic absorption light wavelength of the sub-cell to the solar cell to obtain the target short-circuit current density of the sub-cell.

[0093] Step S230: Based on the first photovoltaic characteristic data and the target short-circuit current density, obtain the second photovoltaic characteristic data of the sub-cell under the specified test light.

[0094] For example, a solar cell may include multiple sub-cells, each of which may have a different characteristic absorption wavelength. Therefore, bias light corresponding to the characteristic absorption wavelength of each sub-cell can be applied to the solar cell separately to obtain first photovoltaic characteristic data for each sub-cell under the bias light. The bias light can be monochromatic light. The first photovoltaic characteristic data may include, for example, the photovoltaic characteristic curve (IV curve) of each sub-cell under the bias light, the ideal performance factor of each sub-cell under the bias light, etc. The photovoltaic characteristic curve includes the relationship between the open-circuit voltage and the short-circuit current density of each sub-cell under the bias light, and the ideal performance factor of the sub-cell may include, for example, the ideal diode factor.

[0095] The specified test light may include standard sunlight (AM1.5G, 100mW / cm²) simulated using a sunlight simulator. -2 ), 0 atmospheric mass sunlight (AM0, 100mWcm) -2 This application primarily uses standard sunlight (AM1.5G, 100mW / cm²) simulated by a solar simulator, and LED light simulated using an LED sunlight simulator. -2 Using LED light as the bias light and specifying the test light, this paper describes the testing method for solar cells.

[0096] By simultaneously applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell, the target short-circuit current density of the sub-cell can be obtained.

[0097] After obtaining the first photovoltaic characteristic data and the target short-circuit current density, further data processing can be performed to obtain the second photovoltaic characteristic data of each sub-cell under the specified test light. The second photovoltaic characteristic data includes, for example, the open-circuit voltage of each sub-cell, the short-circuit current density of each sub-cell, the fill factor of each sub-cell, the photoelectric conversion efficiency of each sub-cell, the contribution value of each sub-cell to the photoelectric conversion efficiency, etc., thereby decoupling the test of the contribution value of each sub-cell to the solar cell efficiency.

[0098] It is understood that the solar cell of this application has only two electrodes and no electrodes are led out between the sub-cells. Therefore, the current density or voltage obtained by this application is for the entire solar cell. However, in some cases, some sub-cells may be current-limited or not functioning. In this case, the relevant parameters of the entire solar cell obtained by testing can be regarded as the parameters of a certain sub-cell.

[0099] According to the embodiments of this application, the first photovoltaic characteristic data of the sub-cell under the bias light is obtained by applying bias light to the solar cell, the target short-circuit current density of the sub-cell is obtained by applying specified test light and bias light, and the second photovoltaic characteristic data of the sub-cell under the specified test light is obtained based on the first photovoltaic characteristic data and the target short-circuit current density. There is no need to add additional devices (such as resistors) to connect to the solar cell to reduce the reverse bias voltage, avoiding the influence of additional devices on the measurement results and improving the test accuracy.

[0100] The following explanation uses a solar cell comprising two sub-cells as an example, namely a first sub-cell and a second sub-cell. In other examples, the first sub-cell may include a narrow bandgap sub-cell, and the second sub-cell may include a wide bandgap sub-cell, wherein the characteristic absorption wavelength of the narrow bandgap sub-cell is greater than that of the wide bandgap sub-cell. For example, the solar cell may include a two-terminal tandem perovskite solar cell with a structure of FTO / NiO. x / MeO-2PACz / WBGPerovskite(CsPbI 3-x Br x ,1.75eV) / C 60 / ALD-SnO2 / Au / PEDOT:PSS / NBG Perovskite(FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3, 1.25eV) / C 60 The / ALD-SnO2 / Cu double-junction all-perovskite tandem solar cell comprises a wide-bandgap cell and a narrow-bandgap cell. The characteristic absorption wavelength of the wide-bandgap cell is 450 nm, and the characteristic absorption wavelength of the narrow-bandgap cell is 750 nm.

[0101] In one example, the testing method for solar cells includes at least some of the following steps S10-S70. For example, it includes at least S20-S50, S10 can be replaced by other feasible methods, and S60-S70 are additional steps added to further improve the testing accuracy. The implementation of each step is described below.

[0102] S10: Obtain the relationship between the overall open-circuit voltage and the overall short-circuit current density of the solar cell under specified test light. The obtained relationship data between the overall open-circuit voltage and the overall short-circuit current density will be used in step S70 below.

[0103] For example, acquiring the IV curve and photovoltaic characteristic data (photovoltaic characteristic parameters) of a solar cell. Specifically, applying a specified test light (100mW cm⁻¹) to a solar simulator. -2 Under AM1.5G conditions, a digital source meter is used to test the two-terminal tandem solar cells to obtain their overall photovoltaic characteristic parameters and photovoltaic characteristic curves. The overall photovoltaic characteristic parameters can be obtained from the photovoltaic characteristic curves, and these parameters may include the short-circuit current density J. SC,Tandem Open circuit voltage V OC,Tandem Fill factor FF Tandem Photoelectric conversion efficiency (PPCE) Tandem etc. Where the subscript Tandem indicates the entire solar cell. Where the short-circuit current density J SC,Tandem and open circuit voltage V OC,Tandem The IV curves between them include data on the relationship between the overall open-circuit voltage and the overall short-circuit current density.

[0104] Specifically, taking an example where the first sub-cell includes a narrow-bandgap sub-cell and the second sub-cell includes a wide-bandgap sub-cell, a specified test light (100mW cm⁻¹) is applied in a solar simulator. -2 Under AM1.5G conditions, a digital source meter was used to test the tandem solar cells at both ends. The specific test procedure is as follows:

[0105] 1. Place the test fixture containing the solar cell on the sample holder, ensuring it is within the measurement plane and that the solar cell is located at the center of the emitted light spot from the solar simulator (or the normal of the solar cell is parallel to the center line of the emitted beam from the solar simulator light source).

[0106] 2. At 100mW cm -2 Under irradiation conditions (standard silicon cells can be used for calibration before testing), a mask is installed on the solar cell, and the temperature of the sample cell is controlled by a temperature monitoring device so that the temperature of the sample under test is maintained at (25±5℃) during the measurement process.

[0107] 3. Set the scanning direction, voltage range, scanning interval voltage, and scanning interval time. The scanning interval should not exceed 0.02V, and the interval between two adjacent points should not be less than 0.3s. Measure the forward and reverse scanning current-voltage characteristics of the sample cell and record the open-circuit voltage (V) of the solar cell. OC ) and short-circuit current density (J SC );

[0108] Photoelectric conversion efficiency (PCE) is as follows:

[0109]

[0110] Among them, J max and V max These represent the maximum output power (P) max The corresponding current density and voltage value, P in J is the incident light power. SC V is the short-circuit current density. OC is the open-circuit voltage, and FF is the fill factor.

[0111] After the test is completed, record the photovoltaic characteristic curve of the solar cell under reverse scanning (e.g., Figure 3 As shown), and the overall short-circuit current density J of the solar cell under reverse scanning was recorded. SC,Tandem Overall open-circuit voltage V OC,Tandem Overall fill factor FF Tandem Overall photoelectric conversion efficiency (PCE) Tandem (As shown in Table 1).

[0112] Table 1

[0113]

[0114] Among them, the obtained overall open-circuit voltage V OC,Tandem and overall short-circuit current density J SC,Tandem The relational data is used in step S70 below.

[0115] S20: Apply bias light corresponding to the characteristic absorption wavelength of the narrow bandgap subcell to the solar cell to obtain data on the relationship between the open-circuit voltage of the narrow bandgap subcell and the irradiation intensity of the bias light; determine the open-circuit voltage corresponding to a specified irradiation intensity as the reference open-circuit voltage of the narrow bandgap subcell. The reference open-circuit voltage of the narrow bandgap subcell is used in step S30.

[0116] For example, such as Figure 4 As shown, bias light (monochromatic light) corresponding to the characteristic absorption wavelength (750 nm) of a narrow bandgap cell is applied to the solar cell. The solar cell is tested using a digital source meter to obtain the irradiance and open-circuit voltage (V) of the narrow bandgap cell with respect to the bias light.OC,NBG1 Dependency curves (e.g.) Figure 5 As shown in the figure), where the subscript NBG indicates a narrow-bandgap subcell. Based on Figure 5 The curve can be used to obtain the reference open-circuit voltage of the narrow-bandgap subcell.

[0117] Specifically, such as Figure 4 As shown, bias light (monochromatic light) corresponding to the characteristic absorption wavelength (750nm) of a narrow bandgap subcell is applied to the solar cell, and the solar cell is tested using a digital source meter (e.g., Figure 4 (As shown). This method is similar to S10, except that the light source used is monochromatic light characteristically absorbed by a narrow bandgap cell (or a long-pass filter is used to filter the spectrum to meet the requirements of narrow bandgap characteristic absorption). In this embodiment, the bandgap of the wide bandgap cell is 1.75 eV, and the bandgap of the narrow bandgap cell is 1.25 eV, so the wide bandgap cell cannot absorb light above 710 nm. Therefore, in this embodiment, 750 nm high-power LED light is used as the characteristic absorption light of the narrow bandgap cell. When 750 nm high-power LED light is applied, the wide bandgap cell does not absorb light, and the measured open-circuit voltage is entirely contributed by the narrow bandgap cell.

[0118] For example, similar to the method in step S10, the difference is that a high-power LED light with a center wavelength of 750nm is used as the illumination light. By changing the irradiance, the IV curve of the two-terminal tandem solar cells is tested, and the open-circuit voltage (V) is recorded. OC,NBG1 The relationship between ) and irradiation intensity (e.g.) Figure 5 The specified irradiation intensity can be 1, when the open-circuit voltage V of the narrow bandgap sub-cell being tested is... OC,NBG1 The irradiance at 0.81V is 1. The open-circuit voltage V... OC，NBG1 =0.81V is used as the reference open-circuit voltage for the narrow bandgap subcell. The reference open-circuit voltage for the narrow bandgap subcell is used in step S30.

[0119] In step S30, bias light corresponding to the characteristic absorption wavelength of the sub-cell is applied to the solar cell to obtain the first photovoltaic characteristic data of the sub-cell under bias light. The first photovoltaic characteristic data includes the relationship data (dependency curve) between the open-circuit voltage and short-circuit current density of the sub-cell under bias light, and the ideal performance factor of the sub-cell under bias light. The relationship data (dependency curve) between the open-circuit voltage and short-circuit current density of the sub-cell under bias light is used in step S50, and the ideal performance factor of the sub-cell is used in step S60.

[0120] In some embodiments, the sub-cell includes a first sub-cell and a second sub-cell; bias light corresponding to the characteristic absorption wavelength of the sub-cell is applied to the solar cell to obtain first photovoltaic characteristic data of the sub-cell under the bias light, including:

[0121] S301, apply bias light corresponding to the characteristic absorption wavelength of the first sub-cell to the solar cell to obtain the first photovoltaic characteristic data of the first sub-cell under the bias light; first photovoltaic characteristic data

[0122] S302, apply bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell to obtain the first photovoltaic characteristic data of the second sub-cell under bias light.

[0123] For example, the first sub-cell includes a narrow bandgap sub-cell, and the second sub-cell includes a wide bandgap sub-cell. The wide bandgap sub-cell has a bandgap of 1.75 eV, while the narrow bandgap sub-cell has a bandgap of 1.25 eV. Therefore, the wide bandgap sub-cell cannot absorb light above 710 nm. Thus, in this embodiment, 750 nm high-power LED light is used as the characteristic absorption light for the narrow bandgap sub-cell. For the wide bandgap sub-cell, a 450 nm high-power LED is used as its characteristic absorption light. In this case, the light is mainly absorbed by the wide bandgap sub-cell, with only a very small amount of light passing through to reach the narrow bandgap sub-cell.

[0124] According to the embodiments of this application, bias light corresponding to the characteristic absorption wavelength is applied to each sub-cell to obtain the first photovoltaic characteristic data of each sub-cell, and the testing method is simple and convenient.

[0125] For example, by applying two beams of bias light (monochromatic light) corresponding to the characteristic absorption light of wide-bandgap and narrow-bandgap solar cells respectively, and using a digital source meter to test the two-terminal tandem solar cells, the dependence between the short-circuit current density and open-circuit voltage of wide-bandgap and narrow-bandgap cells under different irradiation intensities is obtained. Specifically:

[0126] Step S301 may include: for a narrow bandgap subcell, gradually increasing the characteristic absorption light (bias light) of the narrow bandgap subcell while keeping the characteristic absorption light (bias light) of the wide bandgap subcell constant, placing the narrow bandgap subcell in a current-limited state, and testing the solar cell using a digital source meter to obtain the short-circuit current density J of the narrow bandgap subcell under different irradiation intensities. SC,NBG2 and open circuit voltage V OC,NBG2 The dependency curve between them is obtained, and the ideal factor n of the narrow bandgap subcell is calculated based on the dependency curve. id,NBG .

[0127] Step S302 may include: for the wide-bandgap solar cell, gradually increasing the characteristic absorption light of the wide-bandgap solar cell while keeping the characteristic absorption light of the narrow-bandgap solar cell constant; placing the wide-bandgap solar cell in a current-limited state; and using a digital source meter to test the tandem solar cells at both ends to obtain the short-circuit current density J of the wide-bandgap solar cell under different irradiation intensities. SC,WBG2 and open circuit voltage V OC,WBG2The dependency curve between them is obtained, and the ideal factor n of the wide-bandgap subcell is calculated based on the dependency curve. id,WBG .

[0128] For the calculation of the ideality factor, the open-circuit voltage V of any sub-cell is... OC，Subcells2 and They are directly proportional, where n id Here, K is the ideality factor, T is the Kelvin temperature, and q is the elementary charge.

[0129] Specifically, refer to Figure 6 and Figure 7 Two monochromatic beams of light, corresponding to the characteristic absorption light of a wide-bandgap solar cell and a narrow-bandgap solar cell, were applied to the solar cells respectively. A digital source meter was used to test the tandem solar cells at both ends. A high-power LED light source with a center wavelength of 450 nm was used as the characteristic absorption light for the wide-bandgap solar cell, and a high-power LED light source with a center wavelength of 750 nm was used as the characteristic absorption light for the narrow-bandgap solar cell. The specific test steps are as follows:

[0130] Step S301 may specifically include: for a narrow-bandgap solar cell, keeping the 450nm high-power LED light constant (irradiance much greater than that of a 750nm LED light), and gradually increasing the irradiance of the 750nm high-power LED light source (irradiance change consistent with step S20), and testing the IV curve of the solar cell using a method similar to step S10. Since the 450nm LED light intensity is stronger, the narrow-bandgap solar cell is in a current-limited state at this time. As the irradiance of the 750nm LED light source gradually increases, the open-circuit voltage and short-circuit current density of the solar cell will also gradually increase. This increase originates from the narrow-bandgap solar cell (wide-bandgap solar cells do not absorb 750nm LED light). Therefore, the short-circuit current density (J / s) of the narrow-bandgap solar cell under different irradiance intensities is obtained. sc,NBG2 ) and open-circuit voltage (V OC,NBG2 Dependency curves between (e.g.) Figure 7 As shown in the figure, the irradiance is consistent with that in step S20, that is, the 750nm LED light intensity is consistent with the open-circuit voltage in S20. Based on Figure 7 The curve can be further calculated to obtain the ideal performance factor n of the narrow bandgap sub-cell. id,NBG =1.46.

[0131] In some embodiments, applying bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell to obtain first photovoltaic characteristic data of the second sub-cell under bias light further includes: applying bias light corresponding to the characteristic absorption wavelength of the wideband sub-cell to the solar cell to obtain the wideband sub-cell open-circuit voltage and short-circuit current density under bias light; correcting the wideband sub-cell open-circuit voltage based on the reference open-circuit voltage of the narrowband sub-cell to obtain the corrected wideband sub-cell open-circuit voltage; and obtaining the first photovoltaic characteristic data of the wideband sub-cell under bias light based on the corrected wideband sub-cell open-circuit voltage and short-circuit current density. See the following for details.

[0132] For example, step S302 may specifically include: similar to step S301, keeping the 750nm high-power LED light constant (irradiance is a specified irradiance of 1, at which point the reference open-circuit voltage contributed by the narrow-bandgap cell can be obtained from step S20, which is 0.81V), and gradually increasing the irradiance of the 450nm high-power LED light source. The IV curve of the solar cell is tested using a method similar to step S10. Because the 750nm LED light intensity is stronger, the wide-bandgap cell is in a current-limited state at this time. As the irradiance of the 450nm LED light source gradually increases, the open-circuit voltage and short-circuit current density of the solar cell will gradually increase. This increase originates from the wide-bandgap cell (the 450nm LED light is mainly absorbed by the wide-bandgap cell, and very little light reaches the narrow-bandgap cell). Therefore, the short-circuit current density J of the wide-bandgap cell under different irradiances can be obtained. sc,WBG2 Open circuit voltage V OC，WBG2 Dependency curves between them (e.g.) Figure 7 (As shown).

[0133] As shown in step S20 above, the voltage division of the narrow bandgap cell is 0.81V (the reference open-circuit voltage of the narrow bandgap cell). Therefore, the corrected wide bandgap cell open-circuit voltage V can be obtained by subtracting 0.81V from the open-circuit voltage of the solar cell measured under different 450nm LED irradiance. OC，WBG2 .based on Figure 7 The curve can be further calculated to obtain the ideal performance factor n of the wide-bandgap sub-cell. id,WBG =1.85.

[0134] It is understandable that, for narrow-bandgap solar cells and wide-bandgap solar cells, in order to address the issue that when bias light corresponding to the characteristic absorption wavelength of a wide-bandgap solar cell is applied to the solar cell, the narrow-bandgap solar cell absorbs a small portion of the bias light, thus affecting the first photovoltaic characteristic data (including...) of the wide-bandgap solar cell under bias light. Figure 7To address the inaccuracy of the dependency curve and the ideal performance factor of the wideband gap cell, this application corrects the open-circuit voltage of the wideband gap cell based on the reference open-circuit voltage of the narrowband gap cell, thereby improving the accuracy of the first photovoltaic characteristic data of the wideband gap cell under bias light.

[0135] S40: Apply bias light corresponding to the specified test light and the characteristic absorption light wavelength of the sub-cell to the solar cell to obtain the target short-circuit current density of the sub-cell.

[0136] For example, when standard sunlight (100mW cm⁻¹) is applied to a solar cell simultaneously -2 Under the condition of monochromatic light characteristic absorption of AM1.5G and current-limited sub-cells, while keeping the standard sunlight irradiance constant, the monochromatic light characteristic absorption of the current-limited sub-cells gradually increases. A digital source meter is used to test the short-circuit current density (J / s) of the two-terminal tandem solar cells under different irradiance intensities. SC,Tandem1 ) and open-circuit voltage (V OC,Tandem1 The dependence curve of ) was obtained, and the short-circuit current density J of the wide-bandgap cell under standard sunlight was further obtained. SC,WBG The short-circuit current density J of narrow bandgap subcells SC,NBG .

[0137] For example, identifying the current-limiting sub-cell from multiple sub-cells (see below for details on how to identify the current-limiting sub-cell). Figure 13 For example, confirming that the wide-bandgap subcell is a current-limited subcell. Figure 8 As shown, standard sunlight (100mW cm⁻¹) applied by the solar simulator... -2 Under the characteristic absorption light of AM1.5G and wide-bandgap cells corresponding to the bias light (450nm high-power LED illumination), while keeping the irradiance of the solar simulator constant, the irradiance of the 450nm LED bias light is gradually increased. The curves of the short-circuit current density of the solar cell as a function of the bias light relative to the irradiance of the solar cell under different irradiance intensities are tested (e.g., AM1.5G) and wide-bandgap cell characteristic absorption light corresponding to the bias light (450nm high-power LED illumination). Figure 9 (As shown).

[0138] like Figure 9 As shown, firstly, since the wide-bandgap sub-cell is a current-limited sub-cell, the short-circuit current density of the solar cell increases rapidly with the increase of 450nm LED irradiance. When the wide-bandgap sub-cell is no longer current-limited, the currents of the two sub-cells reach equilibrium. When the 450nm LED irradiance is further increased, and the narrow-bandgap sub-cell becomes a current-limited sub-cell, the rate of increase of the short-circuit current density changes (e.g., the rate of increase slows down). The short-circuit current density J of the solar cell under 450nm LED irradiance at different irradiance intensities is recorded. SC,Tandem1 Furthermore, Figure 9 China J SC,Tandem1By extending the points of the rapid rise phase and the slow rise phase to the point where the LED irradiance is 0 at 450 nm (extending to the intersection with the y-axis), the target short-circuit current density J of the wide-bandgap subcell under standard sunlight can be obtained. SC,WBG And the target short-circuit current density J of the narrow bandgap subcell SC,NBG The short-circuit current density J of a wide-bandgap cell SC,WBG and the short-circuit current density J of narrow bandgap subcells SC,NBG Used in step S50.

[0139] S50, the first photovoltaic characteristic data includes the relationship data between the open-circuit voltage and short-circuit current density of the sub-cell under bias light (obtained in S30); based on the first photovoltaic characteristic data (obtained in S30) and the target short-circuit current density (obtained in S40), the second photovoltaic characteristic data of the sub-cell under the specified test light is obtained, including: according to the first preset relationship, based on the target short-circuit current density and the relationship data between the open-circuit voltage and short-circuit current density of the sub-cell, the second photovoltaic characteristic data is obtained.

[0140] For example, the first presupposed relation includes the transformed formula J[V] of the Shockley equation. OC,X2 ] = J SC,X -J SC,X2 [V OC,X2 In the formula, the subscript X represents WBG or NBG.

[0141] Step S30 above yielded the dependence of open-circuit voltage and short-circuit current density of wide and narrow bandgap subcells under different irradiation intensities. Step S40 above yielded the target short-circuit current density J of wide bandgap subcells under standard sunlight. SC,WBG 15.56 mA cm -2 The target short-circuit current density J of a narrow bandgap subcell SC,NBG 17.74 mA cm -2 The dependence of open-circuit voltage and short-circuit current density of wide and narrow bandgap subcells under different irradiance was analyzed. SC,WBG J SC,NBG By substituting the data into the first preset relationship, the ideal photovoltaic characteristic curves of wide and narrow bandgap sub-cells under standard sunlight conditions can be obtained (e.g., Figure 10 The curve was further extracted to obtain the second photovoltaic feature data, which includes photovoltaic feature parameters (as shown in Table 2).

[0142] For example, the second photovoltaic characteristic data includes at least one of the following parameters under specified test light: the open-circuit voltage V of the sub-cell. OC The short-circuit current density J of the sub-cell SCThe fill factor FF of the sub-cell, the photoelectric conversion efficiency PCE of the sub-cell, and the contribution value of the photoelectric conversion efficiency of the sub-cell (the contribution value is the proportion of PCE).

[0143] Table 2

[0144] <![CDATA[J SC (mA cm -2 )]]> <![CDATA[V OC (V)]]> FF PCE WBG 15.56 1.19 84.68％ 15.7％ NBG 17.74 0.79 79.10％ 11.1％

[0145] According to the embodiments of this application, by using a first preset relationship, data fitting can be performed on the target short-circuit current density and the relationship data between the sub-cell open-circuit voltage and the sub-cell short-circuit current density to obtain second photovoltaic characteristic data, thereby improving testing efficiency and convenience.

[0146] The second photovoltaic characteristic data obtained in step 50 above is ideal data. To improve the accuracy of the second photovoltaic characteristics, further data correction can be performed to obtain the corrected second photovoltaic characteristics. The correction process is as follows in steps S60 and S70. Referring to steps S60 and S70, based on the ideal performance factor of the sub-cell (obtained in step S30), the relationship data between the overall open-circuit voltage and the overall short-circuit current density (obtained in step S10), and the second photovoltaic characteristic data (obtained in step S50), the corrected second photovoltaic characteristic data is obtained.

[0147] According to an embodiment of this application, the second photovoltaic characteristic data is ideal data. In order to further improve its accuracy, based on the relationship data of the sub-cell ideal performance factor, the overall open-circuit voltage and the overall short-circuit current density, and the second photovoltaic characteristic data, a corrected second photovoltaic characteristic data is obtained to improve the test accuracy, see S60.

[0148] S60, based on the second preset relationship, the ideal performance factor of the sub-cell and the second photovoltaic characteristic data, the photogenerated current density and the saturated dark current density of the sub-cell are obtained.

[0149] For example, the second presupposed relation includes the Shockley equation. In the formula, J is the current density, J ph Let J0 be the photogenerated current density, J0 be the saturated dark current density, q be the elementary charge, V be the voltage, and n be the voltage. id is the ideal diode factor (obtained from step S30), K is the Boltzmann constant, and T is the thermodynamic temperature.

[0150] Substituting the ideal photovoltaic characteristic curves of the wide and narrow bandgap sub-cells under standard sunlight conditions obtained in step S50 and the ideal performance factor of the sub-cells obtained in step S30 into the second preset relationship for fitting, the photogenerated current density J of the wide and narrow bandgap sub-cells is obtained respectively. ph The saturated dark current density J0 is shown in Table 3.

[0151] Table 3

[0152] <![CDATA[n id ]]> <![CDATA[J ph (mA cm -2 )]]> <![CDATA[J0(mA cm -2 )]]> WBG 1.85 15.5007 <![CDATA[1.5323*10 -10 ]]> NBG 1.46 17.5221 <![CDATA[1.3743*10 -8 ]]>

[0153] S70: Based on the third preset relationship, and using the relationship data of sub-cell photovoltaic current density, sub-cell saturated dark current density, overall open-circuit voltage, and overall short-circuit current density, photovoltaic characteristic fitting data is obtained. Then, S701 or S702 can be executed.

[0154] S701 can directly determine some parameters in the photovoltaic feature fitting data as the corrected second photovoltaic feature data.

[0155] For example, according to Kirchhoff's law V[I Tandem ] = V[I WBG ]+V[I NBG The relationship between the overall open-circuit voltage and overall short-circuit current density obtained in step S10, and the photogenerated current density and saturated dark current density of the sub-cell obtained in step S60, are used to fit the series resistance R of the wide and narrow bandgap sub-cells, respectively. s,WBG and R s,NBG The contribution of wide and narrow bandgap subcells to the photoelectric conversion efficiency of solar cells under standard sunlight conditions was obtained.

[0156] Specifically, the approximate formula for the IV curve of a single diode is as follows:

[0157]

[0158] Among them, R s R is the series resistance of the solar cell. sh R is the parallel resistance of the solar cell, typically... sh Much larger than R s That is, the last item can be omitted, and it can be further simplified to:

[0159]

[0160] The above formula can be further rewritten as:

[0161]

[0162] Therefore, Kirchhoff's law V[I Tandem ] = V[I WBG ]+V[I NBG This can be written as the following formula (this formula is the third preset relationship):

[0163]

[0164] Among them, V[J Tandem The current density of the solar cell is represented by J. Tandem Voltage at time, V[JWBG ] and V[J NBG Similarly, this third preset relationship includes two items (a first sub-preset relationship and a second sub-preset relationship), the first sub-preset relationship... This is the corresponding item for the wide-bandgap subcell, the second sub-preset relationship. This is the item corresponding to narrow bandgap subcells.

[0165] like Figure 11 As shown, the relationship between the overall open-circuit voltage and the overall short-circuit current density obtained through S10 above is as follows: Figure 11 The Tandem (measured) curve in the figure.

[0166] The relationship between the overall open-circuit voltage and overall short-circuit current density obtained in step S10, the photogenerated current density and saturated dark current density of the sub-cell obtained in step S60, and the ideal performance factor of the sub-cell obtained in step S30 are substituted into the third preset relationship for fitting to obtain the series resistance R of the wide and narrow bandgap sub-cells. s,WBG = 2.19Ω·cm 2 and R s,NBG = 2.07Ω·cm 2 Based on the third preset relationship, the overall photovoltaic characteristic fitting data of the solar cell is obtained. The photovoltaic characteristic fitting data includes... Figure 11 The Tandem (fitted) curve in the image. Figure 11 The measured and fitted Tandem curves were calculated separately, and the relevant parameters in Table 4 can be obtained.

[0167] Based on the first sub-preset relationship and the second sub-preset relationship, it can be Figure 11 The Tandem (fitting) curve in the image is split into photovoltaic characteristic fitting data of wide-bandgap sub-cells, such as... Figure 11 The WBG (fitted) curve and the photovoltaic characteristic fitting data of the narrow bandgap sub-cell, such as... Figure 11 The NBG (fitted) curve.

[0168] right Figure 11 The WBG (fitted) curve and NBG (fitted) curve were calculated respectively, and the contribution values ​​of wide and narrow bandgap sub-cells to the photoelectric conversion efficiency of solar cells under standard sunlight conditions, as well as other parameters of the sub-cells, can be obtained, as shown in Table 4.

[0169] The relevant fitting parameters in Table 4 can be used as some parameters in the photovoltaic feature fitting data. These parameters can be determined as the corrected second photovoltaic feature data. When the fitting effect is good, the fitted data is usually more realistic and accurate than the ideal data, thereby improving test accuracy. Alternatively, the photovoltaic feature fitting data can be further processed as described in S702 below to obtain the corrected second photovoltaic feature data.

[0170] Table 4

[0171] <![CDATA[J SC (mA cm -2 )]]> <![CDATA[V OC (V)]]> FF PCE Efficiency Contribution Rate PCE error Tandem 15.75 2.00 79.59％ 25.1％ / / Tandem Fitting 15.75 2.00 83.13％ 26.2％ / 4.38％ WBG fitting 15.53 1.19 83.88％ 15.5％ 59.16％ / NBG fitting 15.75 0.81 84.02％ 10.7％ 40.84％ /

[0172] As shown in Table 4, the PCE error between the Tandem fitted curve and the measured Tandem curve from step S10 is within 5%, indicating a good fitting effect. When the solar cell operates under standard sunlight, the wide bandgap cell contributes 59.16% of the efficiency, and the narrow bandgap cell contributes 40.84% ​​of the efficiency.

[0173] According to an embodiment of this application, the ideal performance factor of the battery and the second photovoltaic characteristic data are fitted based on the second preset relationship to obtain the photocurrent density and the saturation dark current density of the sub-cell. Then, the relationship data of the photocurrent density, the saturation dark current density, the overall open-circuit voltage and the overall short-circuit current density of the sub-cell are further fitted based on the third preset relationship to obtain photovoltaic characteristic fitting data, thereby improving the data fitting effect. Finally, the corrected second photovoltaic characteristic data are obtained based on the photovoltaic characteristic fitting data.

[0174] S702, the photovoltaic feature fitting data obtained in S701 can be further processed to obtain the corrected second photovoltaic feature data.

[0175] For example, photovoltaic feature fitting data includes sub-cell resistance (series resistance R). s,WBG and R s,NBG According to the fourth preset relationship, based on the sub-cell resistance, sub-cell photogenerated current density, sub-cell saturated dark current density, and sub-cell ideal performance factor, the corrected second photovoltaic characteristic data are obtained.

[0176] For example, the obtained sub-cell resistance R s Photogenerated current density of sub-cell J ph Sub-cell saturated dark current density J0, sub-cell ideal performance factor n id Returning to the single diode IV curve formula (fourth preset relationship):

[0177]

[0178] This allows us to obtain corrected second photovoltaic characteristic data for wide and narrow bandgap sub-cells under the standard solar spectrum. The corrected second photovoltaic characteristic data is typically more realistic and accurate than the fitted data, thus improving testing accuracy. Corrected second photovoltaic characteristic data includes, for example, the IV curve (…). Figure 12 ) and photovoltaic characteristic parameters (Table 5).

[0179] Table 5

[0180] <![CDATA[J SC (mA cm -2 )]]> <![CDATA[V OC (V)]]> FF (%) PCE (%) WBG 15.53 1.19 79.27％ 14.7％ NBG 17.74 0.81 75.08％ 10.8％

[0181] According to the embodiments of this application, the sub-cell resistance, sub-cell photogenerated current density, sub-cell saturated dark current density, and sub-cell ideal performance factor are processed based on the fourth preset relationship to obtain the corrected second photovoltaic characteristic data, thereby improving the accuracy and convenience of testing.

[0182] The following describes the specific implementation process of step S220 or step S40 above, which involves applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain the target short-circuit current density of the sub-cell.

[0183] In some cases, the target short-circuit current density of a sub-cell can be determined by calculating the external quantum efficiency (EQE) of a solar cell at different wavelengths. However, for multi-junction solar cells, calculating the target short-circuit current density of a sub-cell using EQE requires applying bias light to put the non-test sub-cells in a photobiased state to eliminate their influence on the tested sub-cell. After applying bias light, the number of incident photons and the number of electrons in the cell are collected to calculate the EQE. This method is susceptible to various factors that can lead to inaccuracies in the EQE calculation. For example, the tested sub-cell may be subjected to a reverse bias voltage from the non-test sub-cells, affecting the accuracy of the short-circuit current density calculation. Therefore, when testing the EQE of multi-junction solar cells, additional photobias and electrical bias are required, making the testing process complex, time-consuming, and easily affected by the settings of these bias parameters. Furthermore, EQE cannot achieve the target short-circuit current density of each sub-cell of a multi-junction solar cell under a specific spectral condition (e.g., monochromatic light). Therefore, there is an urgent need to develop a method to rapidly test the target short-circuit current density of each sub-cell of a multi-junction solar cell.

[0184] Figure 13 A schematic diagram of the process for testing the target short-circuit current density of a sub-battery provided in an embodiment of this application.

[0185] like Figure 13 As shown, applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain the target short-circuit current density of the sub-cell includes steps S1310-S1340.

[0186] The solar cell type specified in this application is a multi-junction solar cell, which is a cell composed of multiple sub-cells made of semiconductor materials with different band gaps connected in series. Since the aforementioned semiconductor materials with different band gaps can absorb light of different wavelengths in the spectrum, the multi-junction solar cell composed of multiple sub-cells can improve the photoelectric conversion efficiency.

[0187] Since solar cells satisfy Kirchhoff's laws, the sub-cell that limits the short-circuit current density of a solar cell can be called a current-limiting sub-cell, the sub-cell with the minimum short-circuit current density can be called the first sub-cell, the sub-cell with the second minimum short-circuit current density can be called the second sub-cell, and so on.

[0188] Step S1310: Apply specified test light conditions to the solar cell, and apply first bias light corresponding to the characteristic absorption wavelength of each sub-cell to the solar cell respectively.

[0189] Specifically, a specified test light is applied to the solar cell, for example, standard sunlight simulated using a solar simulator (AM1.5G, 100mW cm⁻¹). -2 ), 0 atmospheric mass sunlight (AM0, 100mW cm) -2 The text primarily focuses on standard sunlight (AM1.5G, 100mW cm⁻¹) simulated using an LED sunlight simulator. -2 This paper uses a specified test light as an example to illustrate the testing method for solar cells, using LED light as the bias light.

[0190] In one example, a specified test light is first applied to the solar cell, and a digital source meter is used to test the solar cell to obtain the overall photovoltaic short-circuit current density of the solar cell. In addition to applying the specified test light to the solar cell, a first bias light corresponding to the characteristic absorption wavelength of each sub-cell is also applied separately, and the change in the overall short-circuit current density of the solar cell is collected using a digital source meter.

[0191] Step S1320: Based on the first change data of the first short-circuit current density of the solar cell changing with the irradiance of the first bias light, determine the first sub-cell from multiple sub-cells.

[0192] Specifically, by changing the irradiance of the first bias light, a digital source meter is used to collect the first change data of the overall short-circuit current density of the solar cell as it changes with the irradiance of the first bias light. When the first change data shows the fastest change in short-circuit current density with the irradiance of the first bias light, the first sub-cell can be identified among the multiple sub-cells of the solar cell.

[0193] Step S1330: Apply specified test light conditions to the solar cell and apply second bias light corresponding to the characteristic absorption wavelength of the first sub-cell to the solar cell.

[0194] Specifically, after identifying the first sub-cell among multiple sub-cells, a second bias light corresponding to the characteristic absorption wavelength of the first sub-cell can be applied to the solar cell. The second short-circuit current density of the solar cell can be obtained by collecting the change in the overall short-circuit current density of the solar cell through a digital source meter.

[0195] Step S1340: Based on the second variation data of the second short-circuit current density of the solar cell changing with the irradiation intensity of the second bias light, determine the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell.

[0196] Specifically, a second variation data set of the solar cell can be collected using a digital source meter. This second variation data shows the change in the short-circuit current density of the solar cell as the irradiance of the second bias light, corresponding to the characteristic absorption wavelength of the first sub-cell, changes with the intensity of the second bias light. From this second variation data, the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell can be determined.

[0197] Through the embodiments of this application, when the solar cell is under specified test light conditions, by applying additional bias light corresponding to the characteristic absorption wavelength of the sub-cell, the current-limiting sub-cell of the solar cell can be quickly identified. Then, by adjusting the irradiation intensity of the bias light corresponding to the characteristic absorption wavelength of the sub-cell, the target short-circuit current density of each sub-cell can be accurately measured. This method is efficient, simple, and low-cost. The bias light corresponding to the characteristic absorption wavelength can be set, and the irradiation conditions of the bias light can also be changed for testing. Testing is conducted using bias light, and the test conditions are provided by the bias light. The bias light can be adjusted in the test equipment, which has low requirements for the test equipment and is easy to adjust. It can effectively improve the efficiency of judging solar cell process problems in actual production, thereby improving the test effect, reducing the difficulty of testing, and reducing the test cost.

[0198] In another embodiment of this application, determining the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell based on second variation data of the second short-circuit current density of the solar cell changing with the irradiation intensity of the second bias light includes: determining the second short-circuit current density of the solar cell corresponding to the target irradiation intensity based on the second variation data, and using it as the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell.

[0199] In another embodiment of this application, the second change data includes first change trend data and second change trend data, wherein the change trend of the first change trend data is greater than the change trend of the second change trend data; based on the second change data, determining the second short-circuit current density of the solar cell corresponding to the target irradiance intensity as the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell includes: based on the first change trend data, determining the second short-circuit current density of the solar cell corresponding to the first target irradiance intensity as the target short-circuit current density of the first sub-cell; and / or based on the second change trend data, determining the second short-circuit current density of the solar cell corresponding to the second target irradiance intensity as the target short-circuit current density of the second sub-cell.

[0200] According to the embodiments of this application, second change data can be acquired by applying a second bias light once. The second change data includes data with different change trends. The target short-circuit current density of different sub-cells is determined based on the data with different change trends. The target short-circuit current density of two sub-cells can be acquired by applying a second bias light once, which improves the test speed. Furthermore, the target short-circuit current density of the first sub-cell and the target short-circuit current density of the second sub-cell are determined based on the first target irradiance and the second target irradiance, respectively, which improves the test accuracy of the target short-circuit current density.

[0201] In another embodiment of this application, the second variation data is obtained by: acquiring multiple test data points, wherein each test data point includes irradiance and the corresponding second short-circuit current density of the solar cell; and performing data fitting based on the multiple test data points to obtain the second variation data.

[0202] According to the embodiments of this application, the second change data is obtained by fitting multiple test data points, which can improve the testing speed and simplify the testing process by collecting a smaller amount of test data.

[0203] In some embodiments, a double-junction all-perovskite tandem solar cell (including two sub-cells) is used as an example for illustration. The device structure of the double-junction all-perovskite tandem solar cell is FTO / NiO. x / MeO-2PACz / WBGPerovskite(CsPbI 3-x Br x ,1.75eV) / C 60 / ALD-SnO2 / Au / PEDOT:PSS / NBGPerovskite(FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3, 1.25eV) / C 60 / ALD-SnO2 / Cu. Since the double-junction all-perovskite tandem solar cell contains a wide-bandgap cell and a narrow-bandgap cell, a first bias light with a wavelength of 450 nm is selected as the characteristic absorption light of the wide-bandgap cell, and a first bias light with a wavelength of 750 nm is selected as the characteristic absorption light of the narrow-bandgap cell.

[0204] First, in the solar simulator (AM1.5G, 100mWcm) -2 Under irradiation by a solar simulator, the short-circuit current density of the solar cell was tested using a digital source meter. Specifically, the test fixture containing the sample solar cell was placed on the sample holder, positioned within the measurement plane, and the sample solar cell was ensured to be centered on the emitted light spot from the solar simulator (or the photovoltaic cell normal was parallel to the center line of the emitted beam from the solar simulator light source). Then, under irradiation by a solar simulator calibrated with a standard silicon cell, a mask was attached to the sample solar cell, and the temperature of the sample solar cell was controlled using a temperature monitoring device to maintain the temperature of the sample at 25±5℃. Therefore, the overall short-circuit current density of the sample solar cell measured by the digital source meter was J. SCTandem =14.82mAcm -2 .

[0205] Figure 14 This is a schematic diagram illustrating the determination of the first sub-cell of a solar cell according to an embodiment of this application.

[0206] Figure 15 This is a schematic diagram of the fitting curves showing the relationship between the first bias light of a 450nm LED and the short-circuit current density of the solar cell when determining the target short-circuit current density of the first and second sub-cells of the solar cell, as provided in an embodiment of this application.

[0207] Please see Figure 14 and Figure 15 Under solar simulator irradiation, the irradiation light from a 450nm high-power LED (corresponding to the characteristic absorption wavelength of a wide-bandgap perovskite sub-cell) and a 750nm high-power LED (corresponding to the characteristic absorption wavelength of a narrow-bandgap perovskite sub-cell) was used as bias light (first bias light). By gradually increasing the intensity of the first bias light, it was found that as the intensity of the first bias light from the 450nm high-power LED increased, the short-circuit current density of the solar cell increased rapidly, while as the intensity of the first bias light from the 750nm high-power LED increased, the short-circuit current density of the solar cell remained almost unchanged. Therefore, the wide-bandgap perovskite sub-cell corresponding to the 450nm wavelength can be identified as the first sub-cell, and the remaining sub-cell is identified as the second sub-cell. The first bias light from the 450nm high-power LED is then designated as the second bias light.

[0208] Please see Figure 15 , Figure 15 The figure shows the curves illustrating the variation of the short-circuit current density of the solar cell when the bias light intensity is enhanced under irradiation from 450nm high-power LEDs and 750nm high-power LEDs. (Example:) Figure 15 As shown, the horizontal axis x represents the irradiance of the bias light (which can be the relative irradiance of the bias light), and the vertical axis y represents the short-circuit current density of the solar cell.

[0209] The dots represent test data points. Data fitting of multiple dots yields a dotted line (second variation data). The dotted line represents the change in short-circuit current density of the solar cell under the second bias light irradiation of a 450nm high-power LED. It can be seen that the overall short-circuit current density of the solar cell first increases rapidly with the increase of bias light irradiation intensity (first variation trend data), and then remains basically unchanged or increases slowly (second variation trend data).

[0210] Record the short-circuit current density of the solar cell under different irradiation intensities of the second bias light from a 450nm high-power LED, and capture the rapid increase trend of the short-circuit current density. Figure 15 (Solid line with center dot) and a slow upward trend ( Figure 15 By extending the points (dashed lines) outwards to the point where the irradiance of the second bias light of the 450nm high-power LED is 0 (i.e., the target illumination amplitude), the target short-circuit current density J of the wide-bandgap perovskite sub-cell (first sub-cell) under a solar simulator can be obtained. SC，WBG =14.79mAcm -2 The target short-circuit current density J of the narrow bandgap perovskite sub-cell (second sub-cell) SC，NBG =21.86mAcm -2 That is, the y-axis value corresponding to the intersection of the first trend data and the y-axis is the target short-circuit current density of the first sub-cell, and the y-axis value corresponding to the intersection of the second trend data and the y-axis is the target short-circuit current density of the second sub-cell.

[0211] In the embodiments of this application, under specified test light conditions, by applying additional first bias light and second bias light corresponding to the characteristic absorption wavelength of the sub-cell, and by adjusting the irradiance of the first bias light and second bias light, the current-limiting sub-cell of the solar cell can be quickly identified and the target short-circuit current density of each sub-cell can be accurately measured. This method is efficient and simple, and can effectively improve the efficiency of judging solar cell process problems in actual production.

[0212] In another embodiment of this application, the solar cell includes n sub-cells, n≥2; applying a first bias light corresponding to the characteristic absorption wavelength of each sub-cell to the solar cell includes: applying a first bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell to obtain n first change data corresponding one-to-one with the n sub-cells, 1≤i≤n; determining a first sub-cell from the multiple sub-cells based on the first change data of the first short-circuit current density of the solar cell changing with the irradiance of the first bias light includes: determining a target first change data whose data change rate satisfies a first preset rate condition from the n first change data; and determining the sub-cell corresponding to the target first change data as the first sub-cell.

[0213] Specifically, a solar cell is a cell composed of n sub-cells made of semiconductor materials with different band gaps connected in series, where n≥2. When a first bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell is applied to the solar cell (1≤i≤n), the short-circuit current density of the solar cell under the first bias light condition can be measured by a digital source meter.

[0214] By applying a first bias light corresponding to the characteristic absorption wavelengths of the n sub-cells to the solar cell, n first change data points corresponding one-to-one with the n sub-cells can be obtained. Among these n first change data points, the condition that satisfies the fastest rate of change in short-circuit current density is determined as the first preset rate condition. The first change data point that satisfies the first preset rate condition is determined as the target first change data point. That is, the target first change data point is the data point where the short-circuit current density of the solar cell changes fastest under the irradiation intensity of the first bias light. The sub-cell corresponding to the target first change data point is determined as the first sub-cell.

[0215] In the embodiments of this application, when determining the first sub-cell (current-limited sub-cell) from multiple sub-cells, multiple first change data are obtained by applying a first bias light corresponding to the characteristic absorption wavelength of each sub-cell. The sub-cell corresponding to the target first change data whose data change rate satisfies a first preset rate condition (such as the fastest change rate) is determined as the first sub-cell (current-limited sub-cell), thereby improving the testing accuracy and speed of the current-limited sub-cell.

[0216] In one embodiment of this application, the first sub-cell is one of n sub-cells; the method further includes: for the n-1 sub-cells other than the first sub-cell, applying third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell, and collecting the third short-circuit current density of the solar cell, so as to obtain n-1 third change data corresponding one-to-one with the n-1 sub-cells based on the third short-circuit current density of the solar cell, 1≤i≤n-1; determining the target third change data whose data change rate satisfies the second preset rate condition from the n-1 third change data; and determining the sub-cell corresponding to the target third change data as the second sub-cell.

[0217] For example, after determining the first sub-cell among the n sub-cells of a solar cell, the second sub-cell can be determined from the remaining n-1 sub-cells. For instance, for the i-th sub-cell, a third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell is applied to the solar cell. The short-circuit current density of the solar cell is collected using a digital source table to obtain the third change data corresponding to the i-th sub-cell. By applying the third bias light n-1 times respectively, n-1 third change data corresponding one-to-one with the n-1 sub-cells can be obtained, where 1≤i≤n-1. The condition that causes the short-circuit current density of the solar cell to change the fastest is set as the second preset rate condition. When the third change data satisfies the second preset rate condition, the third change data is the target third change data, and its corresponding sub-cell is the second sub-cell.

[0218] According to an embodiment of this application, when determining the second sub-cell (current-limited sub-cell) from multiple sub-cells, multiple third change data are obtained by applying a third bias light corresponding to the characteristic absorption wavelength of each sub-cell. The sub-cell corresponding to the target third change data whose data change rate satisfies a second preset rate condition (e.g., the fastest change rate) is determined as the second sub-cell (current-limited sub-cell), thereby improving the testing accuracy and speed of the current-limited sub-cell.

[0219] In one embodiment of this application, for n-1 sub-cells other than the first sub-cell, applying a third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell includes: applying a third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell based on applying a second bias light whose irradiance intensity meets a preset threshold condition, wherein the irradiance intensity meeting the preset threshold condition includes the irradiance intensity being a preset multiple of a specific irradiance intensity, and the specific irradiance intensity being the irradiance intensity corresponding to the degree to which the change of the second short-circuit current density of the solar cell with the irradiance intensity of the second bias light is less than or equal to a preset degree.

[0220] For example, when n is greater than 2, the above is based on Figure 15The first sub-cell and its target short-circuit current density have been determined, as well as the target short-circuit current density of the second sub-cell. However, it is still uncertain which of the n-1 sub-cells is the second sub-cell. Therefore, it is necessary to further determine the second sub-cell from the n-1 sub-cells.

[0221] When determining the second sub-cell, a specified test light (such as standard sunlight) and two bias lights need to be applied simultaneously to the solar cell. One of the bias lights corresponds to the characteristic absorption wavelength of the first sub-cell (at which point the irradiance of this bias light meets a preset threshold condition), and the other bias light corresponds to the characteristic absorption wavelength of the i-th sub-cell among the n-1 sub-cells. For the irradiance to meet the preset threshold condition, refer to... Figure 15 After determining the first sub-cell of the solar cell, it is possible to... Figure 15 The illumination amplitude corresponding to the inflection point of the dot fitting curve is set as a specific irradiance. When determining the second sub-cell, the illumination amplitude of the bias light corresponding to the characteristic absorption wavelength of the first sub-cell can be a preset multiple of the specific irradiance. The preset multiple can be 2 times, that is, based on the second bias light of twice the intensity, the third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell is applied to the solar cell. For example, the preset multiple can be more than 1 times but less than 2 times. Based on the second bias light of more than 1 times but less than 2 times the intensity, the third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell among n-1 sub-cells is applied to the solar cell.

[0222] After obtaining n-1 third change data corresponding one-to-one with n-1 sub-cells, the target third change data whose data change rate satisfies the second preset rate condition is determined from the n-1 third change data; the sub-cell corresponding to the target third change data is determined as the second sub-cell.

[0223] In the embodiments of this application, on the one hand, by increasing the specific irradiance of the second bias light to twice its original value, the limitation of the first sub-cell on the maximum short-circuit current density of the solar cell can be overcome, so that the first sub-cell is no longer a current-limiting sub-cell. This allows for the identification of the current-limiting second sub-cell among the other sub-cells of the solar cell, enabling rapid identification of the current-limiting sub-cell and accurate measurement of the target short-circuit current density of each sub-cell. On the other hand, by increasing the specific irradiance of the second bias light to more than twice but less than twice its original value, not only can the limitation of the first sub-cell on the maximum short-circuit current density of the solar cell be overcome, but the influence of the bias light corresponding to the characteristic absorption wavelength of the first sub-cell on the second sub-cell can also be reduced, further improving the accuracy of the test results.

[0224] In one embodiment of this application, when n≥3, taking n=3 as an example, by... Figure 15 The first sub-cell, its target short-circuit current density, and the target short-circuit current density of the second sub-cell were determined. Then, based on applying second bias light to the solar cell with an irradiance intensity that meets a preset threshold condition, third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell among the n-1 sub-cells was applied to the solar cell. This was done to determine the second sub-cell based on the data change rate of the n-1 third change data. At this point, the remaining one of the three sub-cells was the third sub-cell.

[0225] Next, it is necessary to further determine the target short-circuit current density of the third sub-cell. When determining the third sub-cell, in addition to applying second bias light to the solar cell with an irradiance meeting a preset threshold condition, a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell must also be applied to the solar cell. For example, under specified test light conditions, the fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell is applied to the solar cell, and the fourth short-circuit current density of the solar cell is collected. Based on the fourth variation data of the solar cell's fourth short-circuit current density with the irradiance of the fourth bias light, the target short-circuit current density of the third sub-cell is determined.

[0226] For example, applying a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell includes: applying the fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell based on the second bias light whose irradiance intensity meets a preset threshold condition. The preset threshold condition includes the irradiance intensity being a preset multiple (which can be greater than 1 and less than 2 times) of a specific irradiance intensity, where the degree of change in the second short-circuit current density of the solar cell with the irradiance intensity of the second bias light is less than or equal to the irradiance intensity corresponding to a preset degree. The specific irradiance intensity and the preset threshold condition are similar to those described above for determining the second sub-cell, and will not be repeated here.

[0227] For example, when there are 3 sub-cells in a solar cell, after the first and second sub-cells are determined by the method described above, the remaining sub-cell is the third sub-cell. The target short-circuit current density of the third sub-cell can be determined by applying a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell of the solar cell, based on the fourth variation data of the fourth short-circuit current density of the solar cell as a function of the irradiation intensity of the fourth bias light.

[0228] To better understand the above content, a triple-junction silicon-perovskite-perovskite tandem solar cell will be used as the test sample for illustration. The narrow-bandgap subcell of the triple-junction silicon-perovskite-perovskite tandem solar cell is a c-Si monocrystalline silicon solar cell with a bandgap of 1.20 eV, while the medium-bandgap subcell is a FA (fiber optic) solar cell. 0.1 Cs 0.9 PbI3 perovskite solar cells with a bandgap of 1.56 eV, and wide-bandgap subcells with Cs. 0.2 FA 0.8 PbI 1.5 Br 1.5 Perovskite solar cells with a band gap of 1.90 eV.

[0229] First, the short-circuit current density of the solar cell was tested using a digital source meter under a solar simulator. The specific testing method was the same as that used in the previous section on testing the short-circuit current density of the double-junction all-perovskite tandem solar cell, and will not be repeated here. The measured short-circuit current density of the solar cell was J. SC,Tandem =7.16mA cm -2 .

[0230] Then, the first sub-cell was identified in the solar cell. The operation method for identifying the first sub-cell is similar to that for identifying the first sub-cell of the double-junction all-perovskite tandem solar cell mentioned above. The irradiance intensity of the second bias light of the 750nm LED corresponding to the characteristic absorption wavelength of the mid-bandgap sub-cell (first sub-cell) was increased, and the short-circuit current density of the solar cell measured by the digital source meter increased rapidly.

[0231] Figure 16 A schematic diagram of the fitting curve showing the relationship between the second bias light of a 750nm LED and the short-circuit current density of a solar cell, provided in an embodiment of this application.

[0232] like Figure 16 As shown, by continuously increasing the irradiance of the 750nm LED second bias light, the short-circuit current density of the solar cell can be measured to rise rapidly and then remain basically constant. Recording the current density of the solar cell under different irradiance intensities of the 750nm LED second bias light allows for fitting the following equation: Figure 16 The curve shown. Furthermore, the rapid rise phase of the short-circuit current density ( Figure 16 (Middle solid line) and the gradual upward phase ( Figure 16 By extending the points (marked by the dashed line) to the point where the irradiance of the second bias light of the 750nm LED is zero, the target short-circuit current density J of the mid-bandgap sub-cell (first sub-cell) of the solar cell under the solar simulator can be obtained. SC，MBG =7.00mAcm -2 And the target short-circuit current density J of the second sub-cell SC,2=10.84mAcm -2 .

[0233] Figure 17 This is a schematic diagram illustrating the determination of the target short-circuit current density of the third sub-cell of a solar cell, as provided in an embodiment of this application.

[0234] Please see Figure 17 To further determine whether the second sub-cell is a narrow-bandgap or wide-bandgap cell, the irradiance of the 750nm LED second bias light needs to be adjusted to twice the specific irradiance under a solar simulator to ensure that the first sub-cell no longer limits the current of the solar cell. While maintaining the 750nm LED second bias light at twice the specific irradiance, additional bias lights from 450nm and 945nm LEDs are used to determine the second sub-cell. As the irradiance of the 450nm LED bias light increases, the short-circuit current density of the solar cell rises rapidly, while as the irradiance of the 945nm LED bias light increases, the short-circuit current density of the solar cell remains almost unchanged. Therefore, the wide-bandgap cell is the second sub-cell of the solar cell, and its short-circuit current density is J. SC,2 =10.84mAcm -2 The narrow bandgap subcell is the third subcell of the solar cell, and the bias light of the 450nm LED is determined as the fourth bias light.

[0235] Figure 18 This is a schematic diagram of the fitting curve showing the relationship between the 450nm LED bias light and the short-circuit current density of the solar cell when determining the target short-circuit current density of the third sub-cell of the solar cell, as provided in an embodiment of this application.

[0236] To further determine the target short-circuit current density of the third sub-cell, similar to the process for determining the second sub-cell described above, based on a solar simulator, the solar cell was simultaneously irradiated with a second bias light from a 750nm LED at twice the specific irradiance, while the irradiance of a fourth bias light from a 450nm LED was continuously increased. The overall short-circuit current density of the solar cell initially increased rapidly and then remained essentially constant. Please refer to [link to relevant documentation]. Figure 18 By extrapolating the points of the slow increase phase of the short-circuit current density to a point where the irradiance of the fourth bias light of the 450nm LED is 0, the target short-circuit current density J of the narrow-bandgap subcell can be obtained. SC,NBG =13.24mA cm -2 .and Figure 18 The phase of rapid increase in short-circuit current density shown above Figure 15 Some of these have already been introduced, so I will not repeat them here.

[0237] Optionally, after all the above steps are completed, the second sub-cell of the solar cell can be redefined. Specifically, the irradiance of the 750nm LED third bias light can be appropriately reduced to a level where the measured short-circuit current density no longer changes significantly during the determination of the second sub-cell (it is only necessary to ensure that the mid-bandgap sub-cell is no longer current-limited), so that the irradiance is more than 1 to 2 times the specific irradiance.

[0238] In another example, when the solar cell has four sub-cells, the method for determining the target short-circuit current density of the first, second, and third sub-cells and their respective sub-cells is the same as the method for determining the target short-circuit current density of the first, second, and third sub-cells and their respective sub-cells in a triple-junction silicon-perovskite-perovskite tandem solar cell. After determining the first, second, and third sub-cells, the fourth sub-cell can be determined. The method for determining the target short-circuit current density of the fourth sub-cell is similar to that for the third sub-cell. The difference is that in determining the target short-circuit current density of the fourth sub-cell, four light sources are actually present: a solar simulator, an LED corresponding to the characteristic absorption wavelength of the first sub-cell, an LED corresponding to the characteristic absorption wavelength of the second sub-cell, and an LED corresponding to the characteristic absorption wavelength of the third sub-cell. By continuously increasing the irradiance of the LED corresponding to the characteristic absorption wavelength of the third sub-cell, the points of the slowly rising phase on the fitted curve are extended to when the irradiance of the LED corresponding to the characteristic absorption wavelength of the first sub-cell is 0, thus obtaining the target short-circuit current density of the fourth sub-cell.

[0239] In the embodiments of this application, under specified test light, by applying additional bias light corresponding to the characteristic absorption wavelength of the sub-cell, and by adjusting the irradiance of the bias light, the current-limiting sub-cells of the solar cell can be quickly identified, and the target short-circuit current density of each sub-cell can be accurately measured. Following this method, when there are multiple sub-cells in the solar cell, the target short-circuit current density of each sub-cell can also be accurately and efficiently determined. Furthermore, the accuracy of the test results can be improved by adjusting the irradiance of the bias light. This method is efficient, simple, and accurate, and can effectively improve the efficiency of identifying process problems in solar cells during actual production.

[0240] Figure 19 This is a flowchart illustrating a testing method for a solar cell provided in an embodiment of this application.

[0241] This application provides a testing method 1900 for a solar cell, the solar cell including a sub-cell, the method including steps S1910-S1930.

[0242] Step S1910: Obtain first photovoltaic characteristic data of the sub-cell under bias light, wherein the first photovoltaic characteristic data is obtained by applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell.

[0243] Step S1920: Obtain the target short-circuit current density of the sub-cell, wherein the target short-circuit current density is obtained by applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell.

[0244] Step S1930: Based on the first photovoltaic characteristic data and the target short-circuit current density, obtain the second photovoltaic characteristic data of the sub-cell under the specified test light.

[0245] For example, the above-described test method 1900 for solar cells can be applied to data processing devices, such as computers.

[0246] Figure 20 This is a schematic diagram of a solar cell testing system provided in an embodiment of this application.

[0247] This application provides a solar cell testing system 2000, such as... Figure 20 As shown, the solar cell testing system 2000 includes:

[0248] Solar cell 2010, solar cell 2010 includes sub-cells.

[0249] The test light device 2020 (such as a solar simulator) is configured to apply a specified test light to the solar cell based on a first control command.

[0250] The bias light device 2030 is configured to apply bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell based on a second control command.

[0251] The acquisition device 2040 (e.g., a digital source meter) is configured to acquire first photovoltaic characteristic data of the sub-cell under bias light when bias light corresponding to the characteristic absorption wavelength of the sub-cell is applied to the solar cell, and to acquire the target short-circuit current density of the sub-cell when a specified test light and bias light corresponding to the characteristic absorption wavelength of the sub-cell are applied to the solar cell.

[0252] The data processing device 2050 is configured to send a first control command to the test light device, send a second control command to the bias light device, acquire first photovoltaic characteristic data and target short-circuit current density from the acquisition device, and obtain second photovoltaic characteristic data of the sub-cell under the specified test light based on the first photovoltaic characteristic data and target short-circuit current density.

[0253] It is understandable that a detailed description of the solar cell testing system 2000 can be found in the description of the solar cell testing methods above.

[0254] Figure 21 This is a schematic diagram of a solar cell testing apparatus provided in an embodiment of this application.

[0255] This application provides a testing apparatus 2100 for solar cells, such as... Figure 21 As shown, the solar cell testing apparatus 2100 includes:

[0256] The first acquisition module 2110 is used to acquire the first photovoltaic feature data of the sub-cell under bias light, wherein the first photovoltaic feature data is obtained by applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell.

[0257] The second acquisition module 2120 is used to acquire the target short-circuit current density of the sub-cell, wherein the target short-circuit current density is obtained by applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell.

[0258] The third acquisition module 2130 is used to obtain the second photovoltaic characteristic data of the sub-cell under specified test light based on the first photovoltaic characteristic data and the target short-circuit current density.

[0259] It is understood that a detailed description of the solar cell testing apparatus 2100 can be found in the description of the solar cell testing method applied to the data processing device above.

[0260] This application provides a computer-readable storage medium in which a computer program, when executed by a processor, implements the steps of any of the above-described embodiments.

[0261] This application provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the method described in any of the above embodiments.

[0262] Figure 22 A block diagram of an electronic device provided in an embodiment of this application.

[0263] This application provides an electronic device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method in any of the above embodiments.

[0264] like Figure 22 As shown, for ease of understanding, embodiments of this application illustrate a specific electronic device 2200.

[0265] Electronic device 2200 is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic device 2200 may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present disclosure described and / or claimed herein.

[0266] like Figure 22 As shown, device 2200 includes a computing unit 2201, which can perform various appropriate actions and processes according to a computer program stored in read-only memory (ROM) 2202 or a computer program loaded from storage unit 2208 into random access memory (RAM) 2203. RAM 2203 may also store various programs and data required for the operation of electronic device 2200. The computing unit 2201, ROM 2202, and RAM 2203 are interconnected via bus 2204. Input / output (I / O) interface 2205 is also connected to bus 2204.

[0267] Multiple components in electronic device 2200 are connected to I / O interface 2205. These components include: input unit 2206, such as a keyboard or mouse; output unit 2207, such as various types of displays or speakers; storage unit 2208, such as a hard disk or optical disk; and communication unit 2209, such as a network interface card (NIC), modem, or wireless transceiver. Communication unit 2209 allows electronic device 2200 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0268] The computing unit 2201 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 2201 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 2201 performs the various methods described above. For example, in some embodiments, any one or more of the methods described above can be implemented as a computer software program tangibly contained in a machine-readable medium, such as storage unit 2208. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 2200 via ROM 2202 and / or communication unit 2209. When the computer program is loaded into RAM 2203 and executed by the computing unit 2201, one or more steps of any one or more of the methods described above can be performed. Alternatively, in other embodiments, the computing unit 2201 can be configured to perform any one or more of the methods described above by any other suitable means (e.g., by means of firmware).

[0269] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequential list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this application, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0270] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0271] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for testing solar cells, characterized in that, The solar cell includes a sub-cell, and the method includes: Apply bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain the first photovoltaic characteristic data of the sub-cell under bias light; Apply a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain the target short-circuit current density of the sub-cell. Based on the first photovoltaic characteristic data and the target short-circuit current density, the second photovoltaic characteristic data of the sub-cell under the specified test light is obtained.

2. The method according to claim 1, characterized in that, The first photovoltaic characteristic data includes the relationship between the sub-cell open-circuit voltage and the sub-cell short-circuit current density under bias light; the step of obtaining the second photovoltaic characteristic data of the sub-cell under specified test light based on the first photovoltaic characteristic data and the target short-circuit current density includes: Based on the first preset relationship, and using the target short-circuit current density and the relationship data between the sub-cell open-circuit voltage and the sub-cell short-circuit current density, the second photovoltaic characteristic data is obtained. The second photovoltaic characteristic data includes at least one of the following parameters under specified test light: open-circuit voltage of sub-cell, short-circuit current density of sub-cell, fill factor of sub-cell, photoelectric conversion efficiency of sub-cell, and contribution value of photoelectric conversion efficiency of sub-cell.

3. The method according to claim 1 or 2, characterized in that, The first photovoltaic characteristic data includes the ideal performance factor of the sub-cell under biased light; the method further includes: Obtain the relationship between the overall open-circuit voltage and the overall short-circuit current density of the solar cell under specified test light; Based on the ideal performance factor of the sub-cell, the relationship data between the overall open-circuit voltage and the overall short-circuit current density, and the second photovoltaic characteristic data, the corrected second photovoltaic characteristic data is obtained.

4. The method according to claim 3, characterized in that, The revised second photovoltaic characteristic data, obtained based on the relationship data between the sub-cell ideal performance factor, the overall open-circuit voltage, and the overall short-circuit current density, and the second photovoltaic characteristic data, includes: Based on the second preset relationship, and using the ideal performance factor of the sub-cell and the second photovoltaic characteristic data, the photogenerated current density and the saturated dark current density of the sub-cell are obtained. Based on the third preset relationship, photovoltaic characteristic fitting data are obtained based on the relationship data of sub-cell photogenerated current density, sub-cell saturated dark current density, overall open-circuit voltage and overall short-circuit current density. Based on the photovoltaic feature fitting data, the corrected second photovoltaic feature data is obtained.

5. The method according to claim 4, characterized in that, The photovoltaic feature fitting data includes the sub-cell resistance; the revised second photovoltaic feature data obtained based on the photovoltaic feature fitting data includes: Based on the fourth preset relationship, and using the sub-cell resistance, the sub-cell photogenerated current density, the sub-cell saturated dark current density, and the sub-cell ideal performance factor, the corrected second photovoltaic characteristic data are obtained.

6. The method according to any one of claims 1-5, characterized in that, The sub-cell includes a first sub-cell and a second sub-cell; the step of applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain the first photovoltaic characteristic data of the sub-cell under the bias light includes: Apply bias light corresponding to the characteristic absorption wavelength of the first sub-cell to the solar cell to obtain the first photovoltaic characteristic data of the first sub-cell under bias light; By applying bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell, the first photovoltaic characteristic data of the second sub-cell under bias light is obtained.

7. The method according to claim 6, characterized in that, The first sub-cell includes a narrow bandgap sub-cell, and the second sub-cell includes a wide bandgap sub-cell, wherein the characteristic absorption wavelength of the narrow bandgap sub-cell is greater than the characteristic absorption wavelength of the wide bandgap sub-cell; the step of applying bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell to obtain the first photovoltaic characteristic data of the second sub-cell under bias light includes: By applying bias light corresponding to the characteristic absorption wavelength of the wideband gap cell to the solar cell, the open-circuit voltage and short-circuit current density of the wideband gap cell under the bias light are obtained. Based on the reference open-circuit voltage of the narrow-bandgap subcell, the open-circuit voltage of the wide-bandgap subcell is corrected to obtain the corrected wide-bandgap subcell open-circuit voltage. Based on the corrected open-circuit voltage and short-circuit current density of the wideband gap cell, the first photovoltaic characteristic data of the wideband gap cell under bias light are obtained.

8. The method according to claim 7, characterized in that, The reference open-circuit voltage of the narrow bandgap sub-cell is obtained in the following way: By applying bias light corresponding to the characteristic absorption wavelength of the narrow bandgap cell to the solar cell, the relationship between the open-circuit voltage of the narrow bandgap cell and the irradiance of the bias light is obtained. The open-circuit voltage corresponding to a specified irradiation intensity is determined as the reference open-circuit voltage of the narrow bandgap subcell.

9. The method according to any one of claims 1-8, characterized in that, The sub-cell comprises multiple sub-cells; the step of applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell to obtain the target short-circuit current density of the sub-cell includes: A specified test light is applied to the solar cell, and a first bias light corresponding to the characteristic absorption wavelength of each sub-cell is applied to the solar cell respectively; Based on first variation data of the first short-circuit current density of the solar cell changing with the irradiance of the first bias light, a first sub-cell is determined from the plurality of sub-cells; A specified test light is applied to the solar cell, and a second bias light corresponding to the characteristic absorption wavelength of the first sub-cell is applied to the solar cell. Based on second variation data showing how the second short-circuit current density of the solar cell changes with the irradiance of the second bias light, the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell are determined.

10. The method according to claim 9, characterized in that, The determination of the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell based on the second variation data of the second short-circuit current density of the solar cell as a function of the irradiation intensity of the second bias light includes: Based on the second change data, the second short-circuit current density of the solar cell corresponding to the target irradiance is determined, and used as the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell.

11. The method according to claim 10, characterized in that, The second change data includes first change trend data and second change trend data, wherein the change trend of the first change trend data is greater than the change trend of the second change trend data; the step of determining the second short-circuit current density of the solar cell corresponding to the target irradiance intensity based on the second change data, as the target short-circuit current density of the first sub-cell and / or the target short-circuit current density of the second sub-cell, includes: Based on the first trend data, the second short-circuit current density of the solar cell corresponding to the first target irradiance is determined, and used as the target short-circuit current density of the first sub-cell; and / or Based on the second trend data, the second short-circuit current density of the solar cell corresponding to the second target irradiance is determined, and used as the target short-circuit current density of the second sub-cell.

12. The method according to any one of claims 9-11, characterized in that, The method further includes obtaining the second change data by: Multiple test data points were acquired, where each test data point included the irradiance and the corresponding second short-circuit current density of the solar cell; The second change data is obtained by fitting data based on the multiple test data points.

13. The method according to any one of claims 9-12, characterized in that, The sub-battery includes n sub-batteries, where n≥2; The step of applying first bias light corresponding to the characteristic absorption wavelength of each sub-cell to the solar cell includes: Apply first bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell to obtain n first change data corresponding one-to-one with the n sub-cells, 1≤i≤n; The determination of a first sub-cell from the plurality of sub-cells based on the first variation data of the first short-circuit current density of the solar cell as a function of the irradiance of the first bias light includes: From the n first change data, determine the target first change data whose data change rate satisfies the first preset rate condition; The sub-battery corresponding to the first change data of the target is determined as the first sub-battery.

14. The method according to claim 13, characterized in that, The first sub-cell is one of the n sub-cells; the method further includes: For the n-1 sub-cells other than the first sub-cell, a third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell is applied to the solar cell, and the third short-circuit current density of the solar cell is collected, so as to obtain n-1 third change data corresponding one-to-one with the n-1 sub-cells based on the third short-circuit current density of the solar cell, 1≤i≤n-1; From the n-1 third change data, determine the target third change data whose data change rate satisfies the second preset rate condition; The sub-battery corresponding to the target third change data is identified as the second sub-battery.

15. The method according to claim 14, characterized in that, The step of applying a third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell to the solar cell for the n-1 sub-cells other than the first sub-cell includes: Based on applying a second bias light whose irradiance meets a preset threshold condition to the solar cell, a third bias light corresponding to the characteristic absorption wavelength of the i-th sub-cell is applied to the solar cell. Among them, the irradiation intensity meeting the preset threshold condition includes the irradiation intensity being a preset multiple of a specific irradiation intensity, wherein the specific irradiation intensity is the irradiation intensity corresponding to the degree to which the change of the second short-circuit current density of the solar cell with the irradiation intensity of the second bias light is less than or equal to the preset degree.

16. The method according to claim 14 or 15, characterized in that, When n≥3, the method further includes: The specified test light is applied to the solar cell, and a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell is applied to the solar cell, and the fourth short-circuit current density of the solar cell is collected. The target short-circuit current density of the third sub-cell is determined based on the fourth variation data of the fourth short-circuit current density of the solar cell as a function of the irradiation intensity of the fourth bias light.

17. The method according to claim 16, characterized in that, Applying a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell to the solar cell includes: Based on applying a second bias light whose irradiance meets a preset threshold condition to the solar cell, a fourth bias light corresponding to the characteristic absorption wavelength of the second sub-cell is applied to the solar cell. Among them, the irradiation intensity meeting the preset threshold condition includes the irradiation intensity being a preset multiple of a specific irradiation intensity, wherein the specific irradiation intensity is the irradiation intensity corresponding to the degree to which the change of the second short-circuit current density of the solar cell with the irradiation intensity of the second bias light is less than or equal to the preset degree.

18. A method for testing solar cells, characterized in that, The solar cell includes a sub-cell, and the method includes: The first photovoltaic characteristic data of the sub-cell under bias light is obtained, wherein the first photovoltaic characteristic data is obtained by applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell; The target short-circuit current density of the sub-cell is obtained by applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell. Based on the first photovoltaic characteristic data and the target short-circuit current density, the second photovoltaic characteristic data of the sub-cell under the specified test light is obtained.

19. A testing system for solar cells, characterized in that, The system includes: Solar cell, the solar cell comprising sub-cells; A test light device is configured to apply a specified test light to the solar cell based on a first control command; A biasing light device is configured to apply bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell based on a second control command. The acquisition device is configured to acquire first photovoltaic characteristic data of the sub-cell under bias light when bias light corresponding to the characteristic absorption wavelength of the sub-cell is applied to the solar cell, and to acquire the target short-circuit current density of the sub-cell when a specified test light and bias light corresponding to the characteristic absorption wavelength of the sub-cell are applied to the solar cell. The data processing device is configured to send the first control command to the test light device, send the second control command to the bias light device, acquire the first photovoltaic characteristic data and the target short-circuit current density from the acquisition device, and obtain the second photovoltaic characteristic data of the sub-cell under the specified test light based on the first photovoltaic characteristic data and the target short-circuit current density.

20. A testing apparatus for solar cells, characterized in that, The solar cell includes a sub-cell, and the device includes: The first acquisition module is used to acquire the first photovoltaic feature data of the sub-cell under bias light, wherein the first photovoltaic feature data is obtained by applying bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell; The second acquisition module is used to acquire the target short-circuit current density of the sub-cell, wherein the target short-circuit current density is obtained by applying a specified test light and a bias light corresponding to the characteristic absorption wavelength of the sub-cell to the solar cell. The third acquisition module is used to obtain the second photovoltaic characteristic data of the sub-cell under specified test light based on the first photovoltaic characteristic data and the target short-circuit current density.

21. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1-18.

22. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1-18.

23. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method according to any one of claims 1-18.

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