A solar cell spatial defect grading diagnosis system and method

Abstract

The application provides a solar cell spatial defect grading diagnosis system and method. The system comprises: an electroluminescence diagnosis module corresponding to an electroluminescence test site, which is used for exciting the electroluminescence phenomenon of a to-be-tested solar cell and collecting the electroluminescence image of the to-be-tested solar cell; at least one level of transient optoelectronic diagnosis module corresponding to at least one optoelectronic test site, which is used for exciting the transient optoelectronic signal in the corresponding target range of the to-be-tested solar cell and collecting the transient optoelectronic property of the to-be-tested solar cell under excitation; a sample table used for holding the to-be-tested solar cell; a precise displacement device used for sequentially locating the sample table at different test sites from the electroluminescence test site to each level of optoelectronic test site; and an automatic control and data processing unit configured to collect the electroluminescence image and the transient optoelectronic property and determine the defect position of the to-be-tested solar cell level by level. The grading research and rapid positioning of the spatial defects of the solar cell are realized.

Description

Technical Field

[0001] This invention relates generally to the field of photoelectric measurement technology, and in particular to a system and method for hierarchical diagnosis of spatial defects in solar cells. Background Technology

[0002] Solar cells are an important clean energy technology that directly converts solar energy into electrical energy and is widely used in industry and daily life. A key focus in solar cell applications is the production of large-area solar cell devices with few defects and uniform performance. Therefore, accurately locating and studying the nature of defects to optimize solar cell manufacturing processes is crucial.

[0003] Currently, techniques such as electroluminescence for studying macroscopic defects and microscopic inhomogeneities such as micro-region JV curves have emerged. However, existing characterization methods either focus only on macroscopic device improvements or are limited to microscopic performance characterization, making them unsuitable for solar cells with different structures or for defect studies of the same solar cell at different scales. Therefore, to meet the research needs of solar cells with different structures and to simultaneously characterize defects in solar cells at both the macroscopic device level and the microscopic uniformity level, there is an urgent need to develop a spatial defect diagnosis scheme that enables rapid location and hierarchical study from macroscopic to microscopic levels. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a solar cell spatial defect classification and diagnosis system and method to overcome or at least partially solve the above problems.

[0005] One objective of this invention is to provide a system and method for hierarchical diagnosis of spatial defects in solar cells, which can enable hierarchical research and rapid location of spatial defects in semiconductor devices such as solar cells.

[0006] A further objective of this invention is to achieve accurate measurement of the transient photoelectric properties of semiconductor devices such as solar cells at different spatial scales.

[0007] Another further objective of the present invention is to further improve the accuracy of defect location.

[0008] Another objective of this invention is to enable defect localization and transient photoelectric property measurement of semiconductor devices such as solar cells with different material systems, structures, sizes, and operating conditions.

[0009] In particular, according to one aspect of the present invention, a solar cell spatial defect grading and diagnostic system is provided, comprising:

[0010] The electroluminescence diagnostic module, corresponding to the electroluminescence test position, is configured to excite the electroluminescence phenomenon of the solar cell under test and acquire the electroluminescence image of the solar cell under test.

[0011] At least one transient photoelectric diagnostic module is provided, corresponding to at least one photoelectric test position. Each transient photoelectric diagnostic module is configured to excite the transient photoelectric signal within the corresponding target range of the solar cell under test and to collect the transient photoelectric properties of the solar cell under test under excitation.

[0012] A sample stage is used to hold the solar cell under test and connect the solar cell under test to the electroluminescence diagnostic module and at least one transient photoelectric diagnostic module.

[0013] A precise displacement device is configured to position the sample stage at different test positions in sequence, from the electroluminescence test position to various photoelectric test positions; and

[0014] An automatic control and data processing unit, connected to an electroluminescence diagnostic module, at least one transient photoelectric diagnostic module, and a precision displacement device, is configured to control the operation of the aforementioned connected components, collect electroluminescence images and transient photoelectric properties, and determine the defect location of the solar cell under test step by step based on the electroluminescence images and transient photoelectric properties.

[0015] Optionally, the electroluminescence diagnostic module includes:

[0016] An adjustable power supply is used to excite the electroluminescence phenomenon of the solar cell under test; and an imager is set up corresponding to the electroluminescence test position to acquire electroluminescence images of the solar cell under test.

[0017] At least one transient photoelectric diagnostic module includes:

[0018] At least one laser source is provided, corresponding to at least one photoelectric test position. Each laser source is configured to generate pulsed laser light to excite transient photoelectric signals within the corresponding target range of the solar cell under test.

[0019] The transient photoelectric measurement unit is used to collect the transient photoelectric properties of the solar cell under test under each laser source excitation.

[0020] The sample stage is also used to connect the solar cell under test to the adjustable power supply and transient photoelectric measurement unit;

[0021] The precision displacement device is also configured to enable spatial scanning of the corresponding target range of the solar cell under test for each stage of the laser light source;

[0022] The automatic control and data processing unit is connected to the adjustable power supply, the imager, each stage of the laser light source, the transient photoelectric measurement unit, and the precision displacement device, and is configured to control the operation of the aforementioned connected components.

[0023] Optionally, the automatic control and data processing unit is also configured to:

[0024] The initial defect region of the solar cell under test is determined based on the electroluminescence image;

[0025] Each laser light source is controlled to perform a spatial scan of the target area of ​​the solar cell under test.

[0026] The transient photoelectric properties acquired under each laser source excitation are collected sequentially. Based on the transient photoelectric properties, the secondary defect region of the solar cell under test corresponding to each laser source is determined. Among them, in at least one laser source, the target range scanned by the first laser source is the initial defect region, the target range scanned by other laser sources is the secondary defect region corresponding to the previous laser source, and the secondary defect region corresponding to the last laser source is the final defect location.

[0027] Optionally, the spot size of the pulsed laser generated by the at least one laser source decreases progressively.

[0028] Optionally, the at least one laser source includes a primary source and a secondary source. The primary source is configured to generate a pulsed laser with a specific frequency, adjustable intensity, and variable spot size in the millimeter range. The secondary source is configured to generate a pulsed laser with a specific frequency and adjustable intensity in the micrometer range.

[0029] Optionally, the primary light source includes:

[0030] Shaping elements are used to output millimeter-scale light spots of the target shape; and a first aperture is used to adjust the intensity of the pulsed laser.

[0031] The secondary light source includes a second aperture, used to adjust the intensity of the pulsed laser.

[0032] Optionally, transient photoelectric properties include transient photocurrent data and / or transient photovoltage data;

[0033] The automatic control and data processing unit is also configured to: process transient photocurrent data and / or transient photovoltage data to obtain corresponding photoelectric result data, and determine the defect location of the solar cell under test step by step based on the electroluminescence image and photoelectric result data, wherein the photoelectric result data includes at least one of transient photovoltage peak value, transient photovoltage lifetime, transient photocurrent peak value, transient photocurrent lifetime, and transient photocurrent integral value.

[0034] Optionally, the solar cell spatial defect grading and diagnostic system also includes:

[0035] One or more optical microscopes are respectively set to correspond to one or more photoelectric test positions in at least one photoelectric test position, and are configured to acquire microscopic images of the solar cell under test at one or more photoelectric test positions;

[0036] The automatic control and data processing unit is also connected to one or more optical microscopes and is configured to collect microscopic images, use the microscopic images to assist the transient photoelectric diagnostic module corresponding to one or more photoelectric test positions in exciting transient photoelectric signals within the corresponding target range of the solar cell under test, and / or use the microscopic images to assist in determining the location of defects.

[0037] Optionally, the precise displacement device includes:

[0038] The system includes a displacement stage for supporting the sample stage; a displacement track for supporting the displacement stage and allowing the displacement stage to move the sample stage along the displacement track in two degrees of freedom (x and y); and a drive element connected to the automatic control and data processing unit for driving the movement of the displacement stage under the control of the automatic control and data processing unit.

[0039] Optionally, the displacement stage includes: a coarse adjustment displacement stage disposed on the displacement track; and a fine adjustment displacement stage disposed on the coarse adjustment displacement stage and supporting the sample stage.

[0040] The driving components include: a coarse adjustment motor for driving the coarse adjustment stage to move on the displacement track with millimeter-level displacement accuracy; and a stepper motor for driving the fine adjustment stage to move on the coarse adjustment stage with micrometer-level displacement accuracy.

[0041] Optionally, the sample stage includes: an adjustable clamp configured to be adjustable according to the size of the solar cell under test to fix solar cells of different sizes; and a probe for contacting the electrodes of the solar cell under test and connecting the solar cell under test to the electroluminescence diagnostic module and at least one transient photoelectric diagnostic module.

[0042] Optionally, the adjustable clamp includes a magnet base and a movable magnetic clamp disposed on the magnet base, wherein the magnet base and the magnetic clamp attract each other to fix the solar cell under test between the magnetic clamps;

[0043] The probe includes a probe arm and / or a conductive film disposed at an adjustable clamp.

[0044] According to another aspect of the present invention, a method for hierarchical diagnosis of spatial defects in solar cells is also provided, comprising:

[0045] A voltage is applied to the solar cell under test located at the electroluminescence test position to excite the electroluminescence phenomenon of the solar cell under test and to obtain the electroluminescence image of the solar cell under test.

[0046] The solar cell under test is sequentially positioned at at least one photoelectric test position. At least one transient photoelectric diagnostic module corresponding to at least one photoelectric test position excites the transient photoelectric signal within the target range of the solar cell under test at each photoelectric test position. The transient photoelectric properties of the solar cell under test under excitation at each photoelectric test position are obtained. The defect location of the solar cell under test is determined step by step based on the electroluminescence image and the transient photoelectric properties.

[0047] Optionally, at least one transient photoelectric diagnostic module includes at least one laser source corresponding to at least one photoelectric test position; the steps of sequentially positioning the solar cell under test at at least one photoelectric test position, exciting transient photoelectric signals within the corresponding target range of the solar cell under test at each photoelectric test position using at least one transient photoelectric diagnostic module corresponding to at least one photoelectric test position, acquiring the transient photoelectric properties of the solar cell under test under excitation at each photoelectric test position, and determining the defect location of the solar cell under test step by step based on the electroluminescence image and transient photoelectric properties include:

[0048] The initial defect region of the solar cell under test is determined based on the electroluminescence image;

[0049] The solar cell under test is sequentially positioned at at least one photoelectric test position. At each photoelectric test position, each laser light source corresponding to the set position is controlled to perform a spatial scan of the target range of the solar cell under test, and the transient photoelectric properties under the excitation of each laser light source are obtained. Based on the transient photoelectric properties, the secondary defect region of the solar cell under test corresponding to each laser light source is determined. Among the at least one laser light source, the target range scanned by the first laser light source is the initial defect region, and the target range scanned by other laser light sources is the secondary defect region corresponding to the previous laser light source. The secondary defect region corresponding to the last laser light source is taken as the final defect location.

[0050] Optionally, the method for grading and diagnosing spatial defects in solar cells also includes:

[0051] Acquire microscopic images of the solar cell under test at one or more photoelectric test positions in at least one photoelectric test position, use the microscopic images to assist the transient photoelectric diagnostic module corresponding to one or more photoelectric test positions in exciting transient photoelectric signals within the corresponding target range of the solar cell under test, and / or use the microscopic images to assist in determining the location of the defects.

[0052] The solar cell spatial defect hierarchical diagnosis system and method provided by the present invention can quickly determine the range of defects by combining electroluminescence detection with at least one level of transient photoelectric property detection, and determine the location of defects through hierarchical diagnosis from macro to micro.

[0053] Furthermore, in the solar cell spatial defect hierarchical diagnosis system and method provided by this invention, the initial defect region is determined by electroluminescence detection, and the corresponding secondary defect regions are determined by each level of transient photoelectric property detection. The target range scanned in the first-level transient photoelectric property detection is the initial defect region, the target range scanned in other levels of transient photoelectric property detection are the secondary defect regions determined by the previous level of transient photoelectric property detection, and the secondary defect region determined by the final level of transient photoelectric property detection is the final defect location. Thus, the same region of the solar cell can be placed on different test positions, enabling the characterization of the solar cell at different scales, greatly simplifying the process of spatial defect location and characterization.

[0054] Furthermore, in the solar cell spatial defect grading diagnosis system and method provided by the present invention, a microscopic image of the solar cell under test is acquired by an optical microscope at one or more photoelectric test positions in at least one photoelectric test position to observe the regional morphology, assist the corresponding laser light source for scanning and detection, and / or assist in locating the defect area, thereby further improving the accuracy of defect location.

[0055] Furthermore, the solar cell spatial defect classification diagnostic system and method provided by the present invention, through the combination of adjustable fixtures, probes and displacement stages with electroluminescence detection and transient photoelectric property detection, can realize defect location and transient photoelectric property measurement of solar cells with different material systems, different structures, different scales and different working conditions.

[0056] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below.

[0057] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0058] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0059] Figure 1 This is a functional structural schematic block diagram of a solar cell spatial defect hierarchical diagnosis system according to an embodiment of the present invention;

[0060] Figure 2 This is a schematic diagram of the sample stage and displacement stage of a solar cell spatial defect grading diagnostic system according to an embodiment of the present invention;

[0061] Figure 3 This is a schematic diagram of the sample stage of a solar cell spatial defect grading and diagnostic system according to an embodiment of the present invention;

[0062] Figure 4 This is a schematic diagram of the sample stage of a solar cell spatial defect grading and diagnostic system according to another embodiment of the present invention;

[0063] Figure 5 This is a schematic diagram of the adjustable transient photoelectric measurement unit of a solar cell spatial defect hierarchical diagnostic system according to an embodiment of the present invention;

[0064] Figure 6 This is a schematic diagram of a solar cell spatial defect hierarchical diagnosis system according to an embodiment of the present invention, which narrows down the range of defects through multi-level diagnosis, wherein the cross symbol indicates the location of the defect;

[0065] Figure 7 This is a schematic diagram of a two-dimensional transient photoelectric scanning of a target area by a solar cell spatial defect hierarchical diagnostic system according to an embodiment of the present invention;

[0066] Figure 8 This is a two-dimensional transient photoelectric scanning visualization result of a solar cell spatial defect hierarchical diagnostic system according to an embodiment of the present invention;

[0067] Figure 9 This is a flowchart illustrating a method for hierarchical diagnosis of spatial defects in solar cells according to an embodiment of the present invention. Detailed Implementation

[0068] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0069] Although methods such as electroluminescence and micro-area JV measurement have been proposed for detecting defects and inhomogeneities in solar cells, an integrated spatial defect diagnosis system applicable to solar cells of different scales and structures has not yet been developed. Defect localization and analysis require the use of multiple devices, consuming significant manpower and time, which is detrimental to the research, promotion, and application of new solar cells. Furthermore, developing an integrated instrument compatible with different solar cells and capable of performing different functions at different scales presents considerable challenges.

[0070] Electroluminescence is an important semiconductor phenomenon widely used for defect detection in the field of solar cells. Its application principle is as follows: By applying a forward bias to the solar cell, non-equilibrium minority carriers cross the potential barrier region and enter the diffusion region. During diffusion, interband recombination of minority carriers generates energy and emits photons. Since the energy and intensity of the emitted photons are closely related to the band gap width, non-equilibrium minority carrier concentration, the proportion of non-radiative recombination, and transmission performance, electroluminescence can reflect the defect distribution of solar cell devices to a certain extent. However, electroluminescence technology alone cannot accurately locate and characterize microscopic defects and inhomogeneities.

[0071] Transient photoelectric measurement technology, including transient photocurrent and transient photovoltage measurements, can be used to study the charge dynamics of devices under short-circuit and open-circuit operating states, and to make qualitative comparisons between different devices. In previous research, the inventors of this application developed adjustable transient photoelectric measurement technology, related physical models, and data processing methods, and invented an adjustable transient photoelectric measurement system that can quantitatively analyze the charge loss of solar cells under different operating states and provide reliable data for defect property studies. However, although existing systems can provide detailed charge dynamics properties of solar cell devices, they can only analyze single regions of a fixed scale in space. They cannot quickly scan and locate defect distributions, nor can they further narrow down the study area to provide more microscopic information.

[0072] To address the aforementioned issues, this invention proposes an integrated spatial defect classification and diagnostic system for solar cells, which enables rapid location and analysis of spatial defects in different solar cells at different scales.

[0073] Figure 1This is a functional structural schematic block diagram of a solar cell spatial defect grading and diagnostic system 100 according to an embodiment of the present invention, wherein straight lines represent circuit or signal connections, arrows represent the direction of the test process, and curly braces indicate that the automatic control and data processing module has circuit or signal connections with other components.

[0074] See Figure 1 As shown, the solar cell spatial defect grading and diagnostic system 100 may include at least: an electroluminescence diagnostic module 200, at least one transient photoelectric diagnostic module 300, a sample stage 150, a precision displacement device 160, and an automatic control and data processing unit 170.

[0075] The electroluminescence diagnostic module 200 corresponds to the electroluminescence test position and is configured to excite the electroluminescence phenomenon of the solar cell under test 180 and acquire the electroluminescence image of the solar cell under test 180.

[0076] At least one transient photoelectric diagnostic module 300 corresponds to at least one photoelectric test position. Each transient photoelectric diagnostic module 300 is configured to excite transient photoelectric signals within the corresponding target range of the solar cell 180 under test and to acquire the transient photoelectric properties of the solar cell 180 under test under excitation.

[0077] The sample stage 150 is used to hold the solar cell under test 180 and connect the solar cell under test 180 to the electroluminescence diagnostic module 200 and at least one transient photoelectric diagnostic module 300.

[0078] The precision displacement device 160 is configured to position the sample stage 150 at different test positions in sequence from the electroluminescence test position to various levels of photoelectric test positions, so as to perform corresponding diagnostics at these test positions. In some alternative embodiments, the precision displacement device 160 can move the sample stage 150 between different test positions by driving the sample stage 150 to move. In other alternative embodiments, the precision displacement device 160 can also position the sample stage 150 sequentially at their corresponding test positions by driving the electroluminescence diagnostic module 200 and at least one level of transient photoelectric diagnostic module 300 to move.

[0079] The automatic control and data processing unit 170 is connected to the electroluminescence diagnostic module 200, at least one transient photoelectric diagnostic module 300 and the precision displacement device 160, respectively. It is configured to control the operation of the aforementioned connected components, collect electroluminescence images and transient photoelectric properties, and determine the defect location of the solar cell 180 under test step by step based on the electroluminescence images and transient photoelectric properties.

[0080] Specifically, the automatic control and data processing unit 170 may be a computer with a built-in automatic control program, which controls the various components connected to it to work together by running the automatic control program.

[0081] The solar cell spatial defect hierarchical diagnosis system 100 provided in this embodiment of the invention can quickly determine the range of defects by combining electroluminescence detection with at least one level of transient photoelectric property detection, and determine the location of defects through hierarchical diagnosis from macro to micro.

[0082] In some embodiments, such as Figure 1 As shown, the electroluminescence diagnostic module 200 may include: an adjustable power supply 110 for exciting the electroluminescence phenomenon of the solar cell 180 under test; and an imager 120, which is set corresponding to the electroluminescence test position for acquiring the electroluminescence image of the solar cell 180 under test.

[0083] The adjustable light source can provide a stable voltage to excite the electroluminescence of solar cells made of different materials. Optionally, the adjustable power supply 110 can cover the operating voltage range of a variety of solar cells.

[0084] Optionally, the spectral curve of the imager 120 covers the visible and infrared regions to monitor the electroluminescence phenomenon of solar cells made of different materials.

[0085] In some embodiments, the imager 120 may include a spectrometer for acquiring and observing spectral distribution data of electroluminescence phenomena, thereby providing an accurate distribution of the electroluminescence spectrum.

[0086] The at least one-stage transient photoelectric diagnostic module 300 may include: at least one stage of laser source 130, each corresponding to at least one photoelectric test position, wherein each stage of laser source 130 is configured to generate pulsed laser to excite transient photoelectric signals within a corresponding target range of the solar cell 180 under test; and a transient photoelectric measurement unit 140 for acquiring the transient photoelectric properties of the solar cell 180 under excitation by each stage of laser source 130. In some embodiments, the number of transient photoelectric measurement units 140 may be the same as the number of laser sources 130, and each stage of laser source 130 and its corresponding transient photoelectric measurement unit 140 constitute a stage of transient photoelectric diagnostic module 300. In other embodiments, the number of transient photoelectric measurement units 140 is one, and each stage of laser source 130 shares this one transient photoelectric measurement unit 140, that is, each stage of laser source 130 and its transient photoelectric measurement unit 140 constitute a stage of transient photoelectric diagnostic module 300, thereby reducing the number of components and saving costs. The preferred approach is to use a single transient photoelectric measurement unit 140 shared by laser light sources 130 at each stage, such as... Figure 1 As shown.

[0087] Accordingly, the sample stage 150 is also used to connect the solar cell under test 180 to the adjustable power supply 110 and the transient photoelectric measurement unit 140. The precision displacement device 160 is also configured to perform spatial scanning of the corresponding target range of the solar cell under test 180 by each stage of the laser light source 130.

[0088] The automatic control and data processing unit 170 is connected to the adjustable power supply 110, the imager 120, each stage of the laser light source 130, the transient photoelectric measurement unit 140, and the precision displacement device 160, and is configured to control the operation of the aforementioned connected components.

[0089] Specifically, the automatic control and data processing unit 170 can control the output of the adjustable power supply 110 to match the working voltage of different solar cells, thereby controlling the adjustable power supply 110 to excite electroluminescence, which is observed by the imager 120 and the signal of the imager 120 is collected; control the pulse frequency of the at least one-stage laser light source 130; record the spatial position of each test position, and control the precision displacement device 160 to place the solar cell under test 180 in different test positions; record the spatial position of the solar cell under test 180, and control the precision displacement device 160 to perform two-dimensional scanning and precise positioning of the same area of ​​the solar cell under test 180 at different test positions; control the working voltage provided by the transient photoelectric measurement unit 140, and collect the signal output by the transient photoelectric measurement unit 140; and analyze the scanning data output by the transient photoelectric measurement unit 140.

[0090] Furthermore, the automatic control and data processing unit 170 can also visualize the signals from the imager 120 and / or the scanning data output by the transient photoelectric measurement unit 140.

[0091] In a further embodiment, the automatic control and data processing unit 170 may also be configured to:

[0092] The initial defect region of the solar cell 180 under test was determined based on the electroluminescence image;

[0093] Each laser source 130 is controlled to perform a spatial scan of the target range of the solar cell 180 under test;

[0094] The transient photoelectric properties acquired under the excitation of each stage of laser source 130 are collected sequentially. Based on the transient photoelectric properties, the secondary defect region of the solar cell 180 under test corresponding to each stage of laser source 130 is determined. Among at least one stage of laser source 130, the target range scanned by the first stage laser source 130 is the initial defect region, the target range scanned by other stages of laser source 130 is the secondary defect region corresponding to the previous stage laser source 130, and the secondary defect region corresponding to the last stage laser source 130 is the final defect location.

[0095] Those skilled in the art will understand that "at least one level" refers to level 1, level 2, or more. In the case of only one level laser source 130, the first-level laser source 130 is also the last-level laser source 130.

[0096] In this embodiment, the same area of ​​the solar cell can be placed on different test positions, and the scanning range of the defect can be gradually reduced, thereby realizing the characterization of the solar cell at different scales, which greatly simplifies the process of spatial defect location and characterization.

[0097] It should be noted that, Figure 1 The number of transient photoelectric diagnostic modules 300 and corresponding laser light sources 130 shown is merely illustrative and does not limit the invention.

[0098] Figure 6 A schematic diagram of a solar cell spatial defect hierarchical diagnostic system 100 according to an embodiment of the present invention is shown, which narrows down the location of defects through multi-level diagnosis, wherein cross symbols indicate the location of defects. Figure 6 As can be seen, at the electroluminescence test position, electroluminescence detection is performed on the electroluminescent region of the solar cell 180 under test to initially determine the defect region (i.e., the initial defect region). Then, at the first photoelectric test position, spatial scanning and transient photoelectric property analysis of the initial defect region using the primary laser source 130 further determine the defect region (i.e., the secondary defect region corresponding to the primary laser source 130). Next, at the next photoelectric test position, spatial scanning and transient photoelectric property analysis of the secondary defect region determined by the next-level laser source 130 determine the secondary defect region corresponding to the next-level laser source 130. This process continues until the secondary defect region corresponding to the final-level laser source 130 is determined at the last photoelectric test position. The secondary defect region corresponding to the final-level laser source 130 is the final defect location (i.e., the location of the cross symbol).

[0099] It should be noted that, Figure 6 The illustration only schematically shows the case of two-stage transient photoelectric detection using a two-stage laser light source 130. However, those skilled in the art will understand that it is equally applicable to cases with a single-stage laser light source 130 or more than two-stage laser light sources 130.

[0100] In some embodiments, the spatial defects of the solar cell 180 under test may be distributed in multiple locations. For example, if multiple initial defect regions are identified at the electroluminescence test sites, the defect locations can be further determined by performing transient photoelectric tests at at least one subsequent photoelectric test site on each initial defect region. Similarly, if multiple secondary defect regions are identified at any primary photoelectric test site, the defect locations can be further determined by performing transient photoelectric tests at each of these secondary defect regions on each subsequent photoelectric test site.

[0101] Furthermore, the spatial distribution of defects can be fully recorded and visualized, and their transient photoelectric properties under different bias voltages can also be stored and analyzed.

[0102] In some embodiments, the spot size of the pulsed laser generated by the at least one-stage laser source 130 decreases progressively. Thus, through the cooperation of the laser source 130 and the precision displacement device 160, more refined scanning analysis at different scales can be achieved.

[0103] In one specific embodiment, the at least one laser source 130 may include two sources: a primary source 130a and a secondary source 130b. The primary source 130a is configured to generate pulsed laser with a specific frequency, adjustable intensity, and variable spot size in the millimeter range. The secondary source 130b is configured to generate pulsed laser with a specific frequency and adjustable intensity in the micrometer range.

[0104] In some further embodiments, the primary light source 130a includes: a shaping element for outputting a millimeter-scale spot of a target shape; and a first aperture for adjusting the intensity of the pulsed laser. The laser passes sequentially through the shaping element and the first aperture to provide a pulsed laser of a specific intensity and shape. Different shaping elements can convert a Gaussian beam into a spot of desired shape and size.

[0105] In some specific embodiments, the primary light source 130a can output a nanosecond-level square light spot with a size in the millimeter range.

[0106] In some further embodiments, the secondary light source 130b includes a second aperture for adjusting the intensity of the pulsed laser. The secondary light source 130b may also include a lens for focusing the laser spot. The laser passes sequentially through the lens and the second aperture to provide pulsed laser light of a specific intensity and size.

[0107] In some specific embodiments, the secondary light source 130b can output a nanosecond-level focused light spot with a size in the micrometer range.

[0108] The primary light source 130a and the secondary light source 130b can each have their own laser, or they can share the same laser. The laser emitted by the laser is split and then enters the optical paths of the optical elements of the primary light source 130a and the secondary light source 130b respectively. Those skilled in the art will understand that this configuration is also applicable to multi-stage laser light sources 130 with two or more stages.

[0109] As mentioned earlier, the precision displacement device 160 can move the sample stage 150 by driving the sample stage 150 to move, or by driving the electroluminescence diagnostic module 200 and at least one transient photoelectric diagnostic module 300 to move, so that the sample stage 150 is sequentially placed in different test positions.

[0110] See Figure 1 In some embodiments, the precision displacement device 160 may include: a displacement stage 161 for supporting the sample stage 150; a displacement track 162 for supporting the displacement stage 161 and allowing the displacement stage 161 to move the sample stage 150 along the displacement track 162 in two-dimensional (x and y) degrees of freedom; and a driving element (not shown) connected to the automatic control and data processing unit 170 for driving the movement of the displacement stage 161 under the control of the automatic control and data processing unit 170. The displacement stage 161 carries the sample stage 150 and moves it on the displacement track 162, serving both scanning and precise positioning functions. Specifically, it can drive the sample to perform one-dimensional or two-dimensional scanning at any test position, and can also precisely position and detect a point on the solar cell 180 under test at any test position.

[0111] The automatic control and data processing unit 170 can control the movement of the displacement stage 161 and read the current spatial coordinates of the displacement stage 161, which is used to test the same position of the solar cell under test 180 at different test positions, perform two-dimensional scanning and precise positioning.

[0112] Figure 2 This is a schematic diagram of the sample stage 150 and displacement stage 161 of a solar cell spatial defect grading and diagnostic system 100 according to an embodiment of the present invention, wherein the direction perpendicular to the image is the y-direction. See also... Figure 2 As shown, in some embodiments, the displacement stage 161 may include: a coarse adjustment displacement stage 1611 disposed on the displacement track 162; and a fine adjustment displacement stage 1612 disposed on the coarse adjustment displacement stage 1611 and supporting the sample stage 150.

[0113] Accordingly, the driving components may include: a coarse adjustment motor for driving the coarse adjustment stage 1611 to move with millimeter-level displacement accuracy on the displacement track 162; and a stepper motor for driving the fine adjustment stage 1612 to move with micrometer-level displacement accuracy on the coarse adjustment stage 1611. Thus, the coarse adjustment stage 1611 carries the fine adjustment stage 1612 and the sample stage 150, moves on the displacement track 162, has two-dimensional degrees of freedom (x and y), and can provide millimeter-level displacement accuracy, enabling rapid movement of the solar cell under test 180 between different test positions or large-amplitude scanning at the same test position. The fine adjustment stage 1612 is mounted on the coarse adjustment stage 1611, carries the sample stage 150, moves on the coarse adjustment stage 1611, has two-dimensional degrees of freedom, and can provide micrometer-level displacement accuracy, enabling fine movement and scanning of the solar cell under test 180 at the test position.

[0114] In a further embodiment, the displacement track 162 may include an x-axis lead screw and a y-axis lead screw. The coarse adjustment motor may include two motors that drive the x-axis lead screw and the y-axis lead screw respectively. Both motors are connected to the automatic control and data processing unit 170 and drive the coarse adjustment displacement stage 1611 to move on the displacement track 162 by driving the lead screws.

[0115] Figure 3 This is a schematic diagram of the sample stage 150 of a solar cell spatial defect grading and diagnostic system 100 according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the sample stage 150 of a solar cell spatial defect grading and diagnostic system 100 according to another embodiment of the present invention.

[0116] See Figure 3 and Figure 4 As shown, in some embodiments, the sample stage 150 may include: an adjustable clamp 151 configured to be adjustable according to the size of the solar cell 180 under test, to fix solar cells 180 of different sizes; and a probe 152 for contacting the electrodes of the solar cell 180 under test and connecting the solar cell 180 under test to the electroluminescence diagnostic module 200 and at least one transient photoelectric diagnostic module 300. Specifically, the probe 152 connects the solar cell 180 under test to the adjustable power supply 110 and the transient photoelectric measurement unit 140.

[0117] The sample stage 150 may also include a base 153. An adjustable clamp 151 and a probe 152 are disposed on the base 153.

[0118] In some further embodiments, such as Figure 3 and Figure 4As shown, the adjustable clamp 151 may include a magnet base 1511 and a movable magnetic clamp 1512 disposed on the magnet base 1511. The magnet base 1511 and the magnetic clamp 1512 attract each other to fix the solar cell 180 under test between the magnetic clamps 1512. The distance between the magnetic clamps 1512 is adjustable to accommodate solar cells of different sizes.

[0119] Specifically, the magnet base 1511 can be a soft magnet or other common magnets.

[0120] In some embodiments, probe 152 may include a probe arm (or robotic probe holder). The probe arm is movable over a wide range and is connected to the electroluminescence diagnostic module 200 and at least one transient photoelectric diagnostic module 300 (specifically, the adjustable power supply 110 and the transient photoelectric measurement unit 140) for connecting solar cells with different electrode structures into the test circuit of the solar cell spatial defect grading diagnostic system 100.

[0121] In other embodiments, such as Figure 4 As shown, probe 152 may include a conductive film disposed at adjustable clamp 151.

[0122] In one specific embodiment, a conductive thin film is disposed on the magnet base 1511 and between the magnetic clamps 1512. This configuration is compatible with diagnostics for solar cells with a back electrode.

[0123] In some other embodiments, probe 152 may include probe arms and a conductive thin film to accommodate solar cells with various electrode structures.

[0124] In some embodiments, the transient photoelectric measurement unit 140 may be an adjustable transient photoelectric measurement unit 140, used to collect transient photoelectric signals generated by the solar cell under test 180 at each photoelectric test position, and output them to the automatic control and data processing unit 170.

[0125] In some optional embodiments, the adjustable transient photoelectric measurement unit 140 can measure the transient photovoltage and transient photocurrent of the solar cell 180 under different bias voltages, and can scan the voltage.

[0126] In some specific embodiments, the adjustable transient photoelectric measurement unit 140 can provide a bias voltage from -10V to 10V and is connected to the probe 152 and the automatic control and data processing unit 170.

[0127] Figure 5 This is a schematic diagram of the adjustable transient photoelectric measurement unit 140 of a solar cell spatial defect grading and diagnostic system 100 according to an embodiment of the present invention. See also... Figure 5As shown, the adjustable transient photoelectric measurement unit 140 may include: a voltage bias module 141 configured to apply a specified bias voltage to the solar cell under test 180 (fixed on the sample stage 150) to put it in a semiconductor electrical state; a filter module 142 connected between the voltage bias module 141 and the solar cell under test 180, configured to make the impedance matching between the measurement circuit of the adjustable transient photoelectric measurement unit 140 and the solar cell under test 180, so that the voltage bias module applies the specified bias voltage to the solar cell under test 180; a sampling resistor module 143 connected in parallel across the filter module 142 and the voltage bias module 141; and an electrical signal measurement module 144 connected to the solar cell under test 180 and the sampling resistor module 143 respectively, configured to acquire the electrical signal output by the solar cell under test 180 through the sampling resistor module under laser excitation.

[0128] Specifically, voltage bias module 141 may include a signal generator and its power supply (such as a DC power supply). Filter module 142 may include multiple filter components with different bandwidths and DC resistance characteristics, thereby enabling impedance matching. Electrical signal measurement module 144 may include a digital oscilloscope, such as a benchtop oscilloscope or a USB oscilloscope.

[0129] In some specific embodiments, the voltage bias module 141 can provide a bias voltage from -10V to 10V.

[0130] In a further embodiment, the adjustable transient photoelectric measurement unit 140 may further include a function switching module 145 connected between the solar cell under test 180 and the filter module 142, configured to be operable to allow the adjustable transient photoelectric measurement unit 140 to switch between different measurement modes.

[0131] Specifically, different measurement modes can include transient photovoltage measurement mode under no voltage regulation mode, transient photocurrent measurement mode under different bias voltages, and transient photovoltage measurement mode under different deviations. Through switching of the function switching module 145, the adjustable transient photoelectric measurement unit 140 can measure the transient photovoltage curve under no voltage regulation mode (also known as non-regulation mode), thereby acquiring the transient photovoltage signal under no voltage regulation mode; or measure the transient photocurrent curve of the solar cell under test 180 under different bias voltages, thereby acquiring the transient photocurrent signal under different scanning voltages; or measure the transient photovoltage curve of the solar cell under test 180 under different bias voltages, thereby acquiring the transient photovoltage signal under different scanning voltages. The function switching module 145 can be implemented by a selection switch, such as a manual single-pole three-throw switch or an electromagnetic relay switch.

[0132] For a more specific description of the adjustable transient photoelectric measurement unit 140, please refer to the adjustable transient photoelectric measurement system previously disclosed by the inventors, which should be readily available and known to those skilled in the art, and will not be elaborated upon here.

[0133] The automatic control and data processing unit 170 can be connected to the electrical signal measurement module 144 and the voltage bias module 141 in the adjustable transient photoelectric measurement unit 140, respectively. It is also configured to: control the voltage output by the voltage bias module 141; read, process, and store the signals acquired by the electrical signal measurement module 144; and coordinate the timing of voltage output by the voltage bias module 141 and signal acquisition by the electrical signal measurement module 144. The automatic control and data processing unit 170 can also be connected to the function switching module 145 to control the mode switching of the adjustable transient photoelectric measurement unit 140.

[0134] In some specific embodiments, the automatic control and data processing unit 170 controls the adjustable power supply 110 to excite the electroluminescence phenomenon and observes it through the imager 120; controls the pulse frequency of each laser light source 130; records the spatial position of each test position and controls the displacement stage 161 to move between different test positions; records the spatial position of the solar cell under test 180 and controls the displacement stage 161 to perform two-dimensional scanning and precise positioning of the same area at different test positions; controls the working voltage provided by the adjustable transient photoelectric measurement unit 140, switches the working mode of the adjustable transient photoelectric measurement unit 140, and collects the signal output by the adjustable transient photoelectric measurement unit 140; and analyzes and visualizes the scanning data output by the adjustable transient photoelectric measurement unit 140.

[0135] In some embodiments, the acquired transient photoelectric properties include transient photocurrent data and / or transient photovoltage data, such as transient photovoltage curves and transient photocurrent curves.

[0136] The automatic control and data processing unit 170 may also be configured to: process transient photocurrent data and / or transient photovoltage data to obtain corresponding photoelectric result data, and determine the defect location of the solar cell 180 under test step by step based on the electroluminescence image and photoelectric result data, wherein the photoelectric result data includes at least one of transient photovoltage peak value, transient photovoltage lifetime, transient photocurrent peak value, transient photocurrent lifetime, and transient photocurrent integral value.

[0137] Still refer to Figure 1 In some embodiments, the solar cell spatial defect grading and diagnostic system 100 may further include one or more optical microscopes 190, which are respectively set to correspond to one or more photoelectric test positions in at least one photoelectric test position and are configured to acquire microscopic images of the solar cell 180 under test at the one or more photoelectric test positions.

[0138] The automatic control and data processing unit 170 is also connected to the one or more optical microscopes 190 and is configured to collect microscopic images, use the microscopic images to assist the transient photoelectric diagnostic module 300 corresponding to the one or more photoelectric test positions in exciting transient photoelectric signals within the target range of the solar cell 180 under test, and / or use the microscopic images to assist in determining the location of defects.

[0139] In this embodiment, a microscopic image of the solar cell under test is acquired by an optical microscope 190 at one or more photoelectric test positions in at least one photoelectric test position to observe the morphology of the area, assist the corresponding laser light source 130 in scanning and detection, and / or assist in locating the defect area, thereby further improving the accuracy of defect location.

[0140] The optical microscope 190 can be used to observe the surface morphology of a specific area of ​​the solar cell 180 under test, and to help locate the irradiation position of the laser source 130 in the corresponding transient photoelectric diagnostic module 300.

[0141] The automatic control and data processing unit 170 can also visualize the microscopic images.

[0142] In some embodiments, the optical microscope 190 has an adjustable magnification to accommodate different scale requirements.

[0143] In some optional embodiments, an optical microscope 190 may be installed at the secondary light source 130b to assist in observing the microstructure of the solar cell 180 under test and to assist in adjusting the irradiation position of the laser from the secondary light source 130b.

[0144] In some embodiments, the automatic control and data processing unit 170 may also perform comparative analysis between the spatial distribution of defects and the surface morphology displayed in electroluminescent images and microscopic images to further explore their possible correlation.

[0145] In some embodiments, the solar cell spatial defect grading and diagnostic system 100 is equipped with two laser light sources 130 for transient photoelectric testing. In this case, the electroluminescent area tested at the electroluminescent test site can cover a decimeter scale, the initial defect area can cover a centimeter scale, the secondary defect area determined by the primary light source 130a can cover a millimeter scale, and the accuracy of the secondary defect area finally located by the secondary light source 130b can reach a micrometer scale.

[0146] In some embodiments, the solar cell spatial defect grading and diagnostic system 100 can be equipped with more than two levels of laser light sources 130. By providing pulsed lasers of different shapes and sizes and displacement stages 161 of different precision, it can adapt to the analysis needs at different scales.

[0147] As mentioned earlier, by controlling the movement of the displacement stage 161 through the automatic control and data processing unit 170, the solar cell spatial defect classification and diagnosis system 100 can perform a two-dimensional spatial scan of the transient electrical properties of the solar cell 180 under test. Figure 7 An exemplary scanning method of the solar cell spatial defect grading diagnostic system 100 is shown for a target area of ​​the solar cell 180 under test. The laser spot is square, and the numerical sequence indicates the scanning order. By controlling the size and step distance of the pulsed laser spot, and setting the bias step of the adjustable transient photoelectric measurement unit 140, the transient electrical properties of a specific region of the solar cell 180 under different bias voltages can be scanned in detail. Figure 7 As shown, each square is a laser irradiation area. After scanning a specific range of bias voltage in the irradiation area, the solar cell under test is stepped 180 steps to the next area for range bias voltage scanning. After several steps, the two-dimensional scan of the target range is completed.

[0148] In some specific embodiments, the shape of the laser spot can be a square of 2mm*2mm, the bias scanning range is -1V to 0.7V, the bias step is 0.05V, the spatial step is 2mm, and the total scanning area size is 12mm*16mm.

[0149] To accommodate the needs of scanning different structures and scales, in some embodiments, the shape, size, bias range, step size, and spatial step distance of the laser spot can be adjusted.

[0150] Figure 8 An exemplary diagram illustrating the visualization of two-dimensional transient photoelectric scanning results from a solar cell spatial defect grading diagnostic system 100 under a specific bias voltage is provided. According to the scanning process, the automatic control and data processing unit 170 can acquire transient photocurrent and transient photovoltage curves for different irradiation regions under various bias voltages. After automated data processing, the peak transient photocurrent, transient photocurrent lifetime, transient photocurrent integral value, peak transient photovoltage, and transient photovoltage lifetime are visualized. In some embodiments, the relative magnitudes of the peak transient photocurrent, transient photocurrent lifetime, transient photocurrent integral value, peak transient photovoltage, and transient photovoltage lifetime are indicated by grayscale, with higher grayscale values ​​representing larger values.

[0151] In order to accurately locate the defect, in some specific embodiments, the quality of the indicated area can be quantitatively calibrated based on the relative magnitudes of the transient photocurrent peak value, transient photocurrent lifetime, transient photocurrent integral value, transient photovoltage peak value, and transient photovoltage lifetime.

[0152] In some further embodiments, the transient photocurrent peak value, transient photocurrent lifetime, transient photocurrent integral value, transient photovoltage peak value, and transient photovoltage lifetime under different bias voltages can be presented separately to study the transient electrical properties of different regions under different operating conditions.

[0153] The solar cell spatial defect classification and diagnostic system 100 provided in this invention can be used to quickly locate the position of spatial defects in solar cells of different scales and structures, and automatically perform spatial scanning measurements of charge dynamics under different bias voltages and illumination conditions to measure and analyze the defect distribution and properties of solar cells. This system features an integrated instrument structure, modular functional area division, complete panel and interface interfaces, and automated control programs, exhibiting high integration and significantly reducing the manpower and time required for spatial defect location, transient photoelectric scanning measurement, and data analysis.

[0154] Furthermore, the solar cell spatial defect classification and diagnosis system 100 provided in this embodiment of the invention can quickly and accurately locate the defect location through the above scanning method and visualization, and can accurately characterize the transient electrical properties of each region, with the advantages of being fast, accurate and non-destructive.

[0155] Based on the same technical concept, the present invention also provides a method for hierarchical diagnosis of spatial defects in solar cells. This diagnostic method can be performed based on the aforementioned hierarchical diagnosis system 100 for solar cells.

[0156] Figure 9 This is a schematic flowchart of a method for hierarchical diagnosis of spatial defects in solar cells according to an embodiment of the present invention. See also... Figure 9 As shown, the method for grading and diagnosing spatial defects in solar cells includes at least the following steps S902 to S904.

[0157] Step S902: Apply voltage to the solar cell 180 under test located at the electroluminescence test position to excite the electroluminescence phenomenon of the solar cell 180 under test and acquire the electroluminescence image of the solar cell 180 under test.

[0158] Step S904: The solar cell under test 180 is sequentially positioned at at least one photoelectric test position. At least one transient photoelectric diagnostic module 300 corresponding to at least one photoelectric test position excites the transient photoelectric signal within the target range of the solar cell under test 180 at each photoelectric test position. The transient photoelectric properties of the solar cell under test 180 under excitation at each photoelectric test position are obtained. The defect location of the solar cell under test 180 is determined step by step based on the electroluminescence image and the transient photoelectric properties.

[0159] In some embodiments, at least one transient photoelectric diagnostic module 300 in the solar cell spatial defect grading diagnostic system 100 includes at least one laser source 130 respectively disposed corresponding to the at least one photoelectric test position.

[0160] Step S904 may specifically include:

[0161] The initial defect region of the solar cell 180 under test was determined based on the electroluminescence image;

[0162] The solar cell under test 180 is sequentially positioned at at least one photoelectric test position. At each photoelectric test position, each laser source 130 is controlled to perform a spatial scan of the target range of the solar cell under test 180, thereby acquiring the transient photoelectric properties under the excitation of each laser source 130. Based on the transient photoelectric properties, the secondary defect region of the solar cell under test 180 corresponding to each laser source 130 is determined. Among the at least one laser source 130, the target range scanned by the first laser source 130 is the initial defect region, and the target range scanned by the other laser sources 130 is the secondary defect region corresponding to the previous laser source 130. The secondary defect region corresponding to the last laser source 130 is taken as the final defect location.

[0163] In some embodiments, transient photoelectric properties include transient photocurrent data and / or transient photovoltage data. Specifically, transient photocurrent data and / or transient photovoltage data may be transient photocurrent curves and / or transient photovoltage curves.

[0164] The operation of determining the secondary defect region of the solar cell 180 under test corresponding to each laser source 130 based on transient photoelectric properties may include:

[0165] The transient photocurrent data and / or transient photovoltage data are processed to obtain the corresponding photoelectric result data, and the secondary defect region of the solar cell 180 under test corresponding to each laser source 130 is determined based on the photoelectric result data. The photoelectric result data includes at least one of the transient photovoltage peak value, transient photovoltage lifetime, transient photocurrent peak value, transient photocurrent lifetime, and transient photocurrent integral value.

[0166] In one specific embodiment, the at least one laser light source 130 includes two light sources, namely a primary light source 130a and a secondary light source 130b.

[0167] The method for grading and diagnosing spatial defects in solar cells specifically includes the following steps:

[0168] (1) Apply a specified voltage to the solar cell 180 under test to excite electroluminescence;

[0169] (2) Based on the electroluminescence image of the solar cell 180 under test acquired by the imager 120, select the defect areas with low brightness and unevenness from the electroluminescence image as the initial defect areas.

[0170] (3) Move the displacement stage 161 to move the initial defect area of ​​the solar cell 180 under test to the first-level photoelectric test position corresponding to the primary light source 130a;

[0171] (4) The transient electrical curves (transient photocurrent curves and / or transient photovoltage curves) of the initial defect region of the solar cell under test 180 are excited by the primary light source 130a, and the displacement stage 161 is moved to realize the two-dimensional scanning of the initial defect region.

[0172] (5) Analyze the two-dimensional scanning transient electrical curves collected by the adjustable transient photoelectric measurement unit 140. By analyzing the transient photovoltage peak, transient photovoltage lifetime, transient photocurrent peak, transient photocurrent lifetime and transient photocurrent integral data in different regions, the defect location is further determined, thereby determining the secondary defect region corresponding to the primary light source 130a (which may be called the first primary defect region, whose range is smaller than the initial defect region).

[0173] (6) Move the displacement stage 161 to move the first-level defect area determined in step (5) to the second-level photoelectric test position corresponding to the secondary light source 130b.

[0174] (7) The transient electrical curve of the first primary defect region of the solar cell under test 180 is excited by the secondary light source 130b, and the displacement stage 161 is moved to realize the two-dimensional scanning of the first primary defect region.

[0175] (8) Analyze the two-dimensional scanning transient electrical curves collected by the adjustable transient photoelectric measurement unit 140, and determine the precise location of the defect (i.e., the secondary defect area corresponding to the secondary light source 130b) by using data such as the peak value of transient photovoltage, transient photovoltage lifetime, peak value of transient photocurrent, transient photocurrent lifetime and transient photocurrent integral in different regions.

[0176] When there are multiple initial defect areas, steps (3) to (8) can be repeated, and the spatial defects of the solar cell under test 180 can be analyzed as a whole.

[0177] In some embodiments, the solar cell spatial defect classification and diagnosis method may further include:

[0178] Acquire microscopic images of the solar cell 180 under test at one or more photoelectric test positions in at least one photoelectric test position, use the microscopic images to assist the transient photoelectric diagnostic module 300 corresponding to one or more photoelectric test positions in exciting transient photoelectric signals within the target range of the solar cell 180 under test, and / or use the microscopic images to assist in determining the defect location.

[0179] The solar cell spatial defect classification and diagnosis method provided in this invention, through the above diagnostic process, can perform defect analysis on solar cells at different scales. This testing process can provide the precise location and transient electrical properties of defects, and can also measure the distribution of transient electrical properties to study the spatial uniformity of solar cells.

[0180] According to the above embodiments, the present invention has the following advantages:

[0181] The solar cell spatial defect hierarchical diagnostic system provided by this invention combines electroluminescence with scanning adjustable transient photocurrent and transient photovoltage to quickly determine the extent of defects and pinpoint the location of micro-defects through hierarchical diagnosis. It also provides two-dimensional scanning transient electrical properties of solar cells and other semiconductor optical devices. This system features an integrated instrument structure, modular functional area division, comprehensive panel and interface interfaces, and automated control programs. Its high integration allows for rapid scanning and analysis of the distribution and properties of spatial defects in solar cells, significantly saving the manpower and time required for macroscopic-to-microscopic defect characterization and two-dimensional scanning transient electrical characterization.

[0182] Furthermore, the solar cell spatial defect hierarchical diagnostic system of the present invention can characterize solar cell devices at different scales at the same location. By calibrating the spatial coordinates of each test position and the laser, this system can place the same area of ​​the solar cell at different test positions using a control program and a displacement stage, greatly simplifying the process of spatial defect location and characterization.

[0183] Furthermore, the solar cell spatial defect hierarchical diagnostic system of the present invention can achieve two-dimensional scanning of the transient electrical properties of solar cells under different operating voltages by controlling the laser spot size and the stepping distance of the displacement stage. Simultaneously, through an automated processing program, the peak transient photovoltage, transient photovoltage lifetime, peak transient photocurrent, transient photocurrent lifetime, and transient photocurrent integral value of the solar cells under different operating voltages can be presented in two dimensions for visualization, thereby making the spatial distribution of defects clearer and more concise. Moreover, the spatial distribution of transient electrical properties can be combined with electroluminescence distribution and morphological features for analysis, thereby establishing a possible correlation.

[0184] The solution of this invention can also be applied to other semiconductor devices.

[0185] The technical features in the above embodiments can be combined arbitrarily. For the sake of simplicity, not all possible combinations in the above embodiments are described in detail. However, any combination of these technical features that does not contradict each other should be considered within the scope of this specification.

[0186] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0187] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A spatial defect classification and diagnostic system for solar cells, characterized in that, include: An electroluminescence diagnostic module, corresponding to the electroluminescence test position, is configured to excite the electroluminescence phenomenon of the solar cell under test and acquire the electroluminescence image of the solar cell under test; At least one transient photoelectric diagnostic module is provided, corresponding to at least one photoelectric test position. Each transient photoelectric diagnostic module is configured to excite the transient photoelectric signal within the corresponding target range of the solar cell under test and to collect the transient photoelectric properties of the solar cell under test under excitation. A sample stage is used to hold the solar cell under test and connect the solar cell under test to the electroluminescence diagnostic module and the at least one transient photoelectric diagnostic module. A precise displacement device is configured to position the sample stage at different test positions in sequence from the electroluminescence test position to various photoelectric test positions; and An automatic control and data processing unit, connected to the electroluminescence diagnostic module, the at least one-level transient photoelectric diagnostic module, and the precise displacement device, is configured to control the operation of the aforementioned connected components, collect the electroluminescence image and the transient photoelectric properties, and determine the defect location of the solar cell under test step by step based on the electroluminescence image and the transient photoelectric properties.

2. The solar cell spatial defect hierarchical diagnostic system according to claim 1, characterized in that, The electroluminescence diagnostic module includes: An adjustable power supply is used to excite the electroluminescence phenomenon of the solar cell under test; and an imager is set corresponding to the electroluminescence test position to acquire the electroluminescence image of the solar cell under test. The at least one transient photoelectric diagnostic module includes: At least one laser source is provided, corresponding to each of the at least one photoelectric test positions. Each laser source is configured to generate pulsed laser light to excite transient photoelectric signals within the corresponding target range of the solar cell under test. The transient photoelectric measurement unit is used to collect the transient photoelectric properties of the solar cell under test under each stage of laser light source excitation. The sample stage is also used to connect the solar cell under test to the adjustable power supply and the transient photoelectric measurement unit; The precise displacement device is also configured to enable spatial scanning of the corresponding target range of the solar cell under test by each stage of the laser light source; The automatic control and data processing unit is connected to the adjustable power supply, the imager, each stage of the laser source, the transient photoelectric measurement unit, and the precision displacement device, and is configured to control the operation of the aforementioned connected components.

3. The solar cell spatial defect hierarchical diagnostic system according to claim 2, characterized in that, The automatic control and data processing unit is further configured to: The initial defect region of the solar cell under test is determined based on the electroluminescence image; Each stage of the laser light source is controlled to perform a spatial scan of the target range of the solar cell under test. The transient photoelectric properties acquired under the excitation of each stage of the laser source are collected sequentially. Based on the transient photoelectric properties, the secondary defect region of the solar cell under test corresponding to each stage of the laser source is determined. Among the at least one stage of the laser source, the target range scanned by the first stage of the laser source is the initial defect region, the target range scanned by the other stages of the laser source is the secondary defect region corresponding to the previous stage of the laser source, and the secondary defect region corresponding to the last stage of the laser source is the final defect location.

4. The solar cell spatial defect hierarchical diagnostic system according to claim 2, characterized in that, The spot size of the pulsed laser generated by the at least one laser source decreases progressively.

5. The solar cell spatial defect hierarchical diagnostic system according to claim 4, characterized in that, The at least one laser source includes a primary source and a secondary source. The primary source is configured to generate a pulsed laser with a specific frequency, adjustable intensity, and variable spot size in the millimeter range. The secondary source is configured to generate a pulsed laser with a specific frequency and adjustable intensity in the micrometer range in the micrometer range.

6. The solar cell spatial defect hierarchical diagnostic system according to claim 5, characterized in that, The primary light source includes: Shaping elements are used to output millimeter-scale light spots of the target shape; and The first aperture is used to adjust the intensity of the pulsed laser; The secondary light source includes: The second aperture is used to adjust the intensity of the pulsed laser.

7. The solar cell spatial defect hierarchical diagnostic system according to claim 1, characterized in that, The transient photoelectric properties include transient photocurrent data and / or transient photovoltage data; The automatic control and data processing unit is further configured to: process the transient photocurrent data and / or transient photovoltage data to obtain corresponding photoelectric result data, and determine the defect location of the solar cell under test step by step according to the electroluminescent image and the photoelectric result data, wherein the photoelectric result data includes at least one of transient photovoltage peak value, transient photovoltage lifetime, transient photocurrent peak value, transient photocurrent lifetime, and transient photocurrent integral value.

8. The solar cell spatial defect classification and diagnostic system according to any one of claims 1-7, characterized in that, Also includes: One or more optical microscopes are respectively set to correspond to one or more photoelectric test positions in the at least one photoelectric test position, and are configured to acquire microscopic images of the solar cell under test at the one or more photoelectric test positions respectively; The automatic control and data processing unit is also connected to the one or more optical microscopes and is configured to collect the microscopic images, use the microscopic images to assist the transient photoelectric diagnostic module corresponding to the one or more photoelectric test positions in exciting the transient photoelectric signal within the corresponding target range of the solar cell under test, and / or use the microscopic images to assist in determining the defect location.

9. The solar cell spatial defect hierarchical diagnostic system according to any one of claims 1-7, characterized in that, The precise displacement device includes: A displacement stage is used to support the sample stage; A displacement track is provided to support the displacement stage and allow the displacement stage to move the sample stage along the displacement track in two dimensions (x and y). A driving element, connected to the automatic control and data processing unit, is used to drive the movement of the displacement stage under the control of the automatic control and data processing unit.

10. The solar cell spatial defect hierarchical diagnostic system according to claim 9, characterized in that, The displacement stage includes: A coarse adjustment displacement stage is set on the displacement track; and A fine-tuning displacement stage is set on the coarse-tuning displacement stage and supports the sample stage; The driving element includes: A coarse adjustment motor is used to drive the coarse adjustment displacement stage to move on the displacement track with millimeter-level displacement accuracy; and A stepper motor is used to drive the fine-tuning displacement stage to move on the coarse-tuning displacement stage with micron-level displacement accuracy.

11. The solar cell spatial defect grading and diagnostic system according to any one of claims 1-7, characterized in that, The sample stage includes: An adjustable clamp, configured to be adjustable according to the size of the solar cell under test, to fix solar cells under test of different sizes; and A probe is used to contact the electrodes of the solar cell under test and connect the solar cell under test to the electroluminescence diagnostic module and the at least one transient photoelectric diagnostic module.

12. The solar cell spatial defect hierarchical diagnostic system according to claim 11, characterized in that, The adjustable clamp includes a magnet base and a movable magnetic clamp disposed on the magnet base. The magnet base and the magnetic clamp attract each other to fix the solar cell under test between the magnetic clamps. The probe includes a probe arm and / or a conductive film disposed at the adjustable clamp.

13. A method for hierarchical diagnosis of spatial defects in solar cells, characterized in that, include: A voltage is applied to the solar cell under test located at the electroluminescence test position to excite the electroluminescence phenomenon of the solar cell under test, and an electroluminescence image of the solar cell under test is obtained. The solar cell under test is sequentially positioned at at least one photoelectric test position. At least one transient photoelectric diagnostic module corresponding to the at least one photoelectric test position excites the transient photoelectric signal within the corresponding target range of the solar cell under test at each of the photoelectric test positions. The transient photoelectric properties of the solar cell under test under excitation at each of the photoelectric test positions are obtained. The defect location of the solar cell under test is determined step by step based on the electroluminescence image and the transient photoelectric properties.

14. The method for hierarchical diagnosis of spatial defects in solar cells according to claim 13, characterized in that, The at least one-level transient photoelectric diagnostic module includes at least one laser source corresponding to each of the at least one photoelectric test position; the step of sequentially positioning the solar cell under test at at least one photoelectric test position, exciting transient photoelectric signals within a corresponding target range of the solar cell under test at each of the at least one photoelectric test positions using the at least one-level transient photoelectric diagnostic module corresponding to each of the at least one photoelectric test positions, acquiring the transient photoelectric properties of the solar cell under test under excitation at each of the photoelectric test positions, and determining the defect location of the solar cell under test step by step based on the electroluminescence image and the transient photoelectric properties includes: The initial defect region of the solar cell under test is determined based on the electroluminescence image; The solar cell under test is sequentially positioned at at least one photoelectric test position. At each photoelectric test position, the corresponding laser light source is controlled to perform a spatial scan of the target range of the solar cell under test, thereby acquiring the transient photoelectric properties under the excitation of each laser light source. Based on the transient photoelectric properties, the secondary defect region of the solar cell under test corresponding to each laser light source is determined. Among the at least one laser light source, the target range scanned by the first laser light source is the initial defect region, and the target range scanned by the other laser light sources is the secondary defect region corresponding to the previous laser light source. The secondary defect region corresponding to the last laser light source is taken as the final defect location.

15. The method for hierarchical diagnosis of spatial defects in solar cells according to claim 13 or 14, characterized in that, Also includes: Acquire a microscopic image of the solar cell under test at one or more of the at least one photoelectric test positions, use the microscopic image to assist the transient photoelectric diagnostic module corresponding to the one or more photoelectric test positions in exciting the transient photoelectric signal within the corresponding target range of the solar cell under test, and / or use the microscopic image to assist in determining the defect location.

Images