Solar cell micro-area property scanning system

Abstract

The utility model provides a solar cell micro-area property scanning system, comprising a one-dimensional laser light source configured to generate one-dimensional line scanning laser; the sample table is used for holding a solar cell sample to be tested; the accurate displacement device is configured to enable the one-dimensional laser light source and the sample table to move relatively so as to enable the one-dimensional line scanning laser to scan a to-be-measured area, comprising a plurality of micro-areas, of the solar cell sample in a cross scanning mode; the micro-area property measuring unit is configured to collect property data of the scanned to-be-measured area; and the automatic control and data processing unit is configured to collect the property data from the microcell property measuring unit, extract property information at the vertical intersection of the cross scanning according to the property data, and determine the distribution of the microcell properties according to the property information at the vertical intersection. Therefore, the stepping times required by micro-area scanning can be reduced, the scanning time is shortened, and the sampling times are reduced.

Description

Technical Field

[0001] This utility model relates to the field of photoelectric measurement technology, and in particular to a micro-area property scanning system for solar cells. Background Technology

[0002] Solar cells are an important clean energy technology that converts solar energy into electricity and is widely used in daily life. A crucial aspect of solar cell manufacturing is characterizing the micro-region properties of solar cells, studying their inhomogeneities and defects to optimize the manufacturing process. Currently, techniques such as micro-region JV testing and micro-region fluorescence have emerged to study microscopic inhomogeneities. However, existing micro-region testing methods collect signals by precisely illuminating specific areas; this point-by-point scanning method is time-consuming and cannot meet the demands of high-throughput, mass testing.

[0003] Furthermore, while existing systems can provide detailed charge dynamics properties of solar cell devices, the time required increases a thousandfold when micro-area spatial scanning is involved. Therefore, to meet the demands of industrial-scale solar cell production and achieve rapid micro-area scanning characterization of a large number of cells, it is urgent to propose a scanning system that can both preserve micro-area information and significantly accelerate the scanning speed. Utility Model Content

[0004] In view of the above problems, this utility model proposes a solar cell micro-area property scanning system that overcomes or at least partially solves the above problems.

[0005] One objective of this invention is to provide a solar cell micro-area property scanning system that can achieve rapid scanning of the properties of solar cell micro-areas by acquiring micro-area information through one-dimensional line laser cross-scanning, thereby significantly reducing the number of steps required for micro-area scanning.

[0006] A further objective of this invention is to achieve rapid scanning and processing of the transient photoelectric properties of micro-regions in solar cells.

[0007] In particular, according to one aspect of the present invention, a micro-area property scanning system for solar cells is provided, comprising:

[0008] A one-dimensional laser source configured to generate a one-dimensional line scan laser of a specified size and frequency;

[0009] A sample stage is used to hold the solar cell sample to be tested and to connect the solar cell sample to the micro-area property measurement unit;

[0010] A precision displacement device is configured to cause relative movement between the one-dimensional laser source and the sample stage, so that the one-dimensional line scanning laser scans the measurable region of the solar cell sample, which includes multiple micro-regions, in a cross-scan manner.

[0011] The micro-area property measurement unit is configured to acquire property data of the scanned area to be measured; and

[0012] An automatic control and data processing unit is connected to the one-dimensional laser source, the precise displacement device, and the micro-area property measurement unit, respectively. It is configured to control the operation of the precise displacement device and the one-dimensional laser source, collect property data from the micro-area property measurement unit, extract property information at the vertical intersection of the cross-scan based on the property data, and determine the distribution of micro-area properties based on the property information at the vertical intersection.

[0013] Optionally, the precise displacement device includes:

[0014] A displacement stage is used to support the sample stage;

[0015] 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).

[0016] A driving element is used to drive the displacement stage to move along the displacement track.

[0017] Optionally, the displacement track includes an x-axis lead screw and a y-axis lead screw;

[0018] The driving element includes two motors that drive the x-axis lead screw and the y-axis lead screw respectively, and both motors are connected to the automatic control and data processing unit.

[0019] Optionally, the sample stage includes:

[0020] An adjustable clamp, configured to be adjustable according to the size of the solar cell sample to be tested, to fix solar cell samples of different sizes to be tested; and

[0021] A probe is used to contact the electrodes of the solar cell sample and connect the solar cell sample to the micro-area property measurement unit.

[0022] Optionally, the adjustable clamp is a magnetic clamp.

[0023] Optionally, the one-dimensional laser source includes:

[0024] Laser attenuator, used to adjust the intensity of the laser;

[0025] A cylindrical lens, positioned downstream of the laser attenuator, is used to convert the incident laser into a one-dimensional line laser of a specific size; and

[0026] An adjustable aperture is located downstream of the cylindrical lens in the optical path and is used to adjust the size of the one-dimensional line laser.

[0027] Optionally, the micro-area property measurement unit is an adjustable transient photoelectric measurement unit.

[0028] Optionally, the adjustable transient photoelectric measurement unit includes:

[0029] A voltage bias module is configured to apply a specified bias voltage to the solar cell sample to place it in a semiconductor electrical state.

[0030] A filter module, connected between the voltage bias module and the solar cell sample, is configured to impedance match between the measurement circuit of the adjustable transient photoelectric measurement unit and the solar cell sample, so that the voltage bias module applies the specified bias voltage to the solar cell sample.

[0031] A sampling resistor module is connected in parallel across the filter module and the voltage bias module; and

[0032] An electrical signal measurement module is connected to both the solar cell sample and the sampling resistor module, and is configured to acquire the electrical signal of the solar cell sample under the excitation of the one-dimensional line scanning laser.

[0033] Optionally, the adjustable transient photoelectric measurement unit further includes:

[0034] A function switching module, connected between the solar cell sample and the filter module, is configured to be operable to allow the adjustable transient photoelectric measurement unit to switch between different measurement modes.

[0035] Optionally, the automatic control and data processing unit includes a computer with built-in automatic control programs.

[0036] The solar cell micro-area property scanning system provided by this invention achieves rapid scanning of the micro-area properties of the solar cell sample by causing relative movement between a one-dimensional laser source and the sample stage. This is achieved through cross-scanning of multiple micro-areas of the solar cell sample held on the sample stage by a one-dimensional line scanning laser emitted from the laser source. The system automatically collects and processes the micro-area property data, extracts property information at the perpendicular intersections of the cross-scans, and determines the distribution of micro-area properties based on this information. By acquiring micro-area information through one-dimensional line laser cross-scanning, the number of steps required for micro-area scanning can be significantly reduced, thereby greatly shortening the scanning time and reducing the number of sampling operations.

[0037] Furthermore, the solar cell micro-area property scanning system provided by this utility model adopts an adjustable transient photoelectric measurement unit, which can realize rapid scanning and processing of transient photoelectric properties of solar cell micro-areas.

[0038] Furthermore, the solar cell micro-area property scanning system provided by this utility model achieves precise control over the position and movement of the sample stage by employing a combination of a displacement stage and a displacement track, thereby ensuring the accuracy of cross-scanning.

[0039] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model 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 utility model more obvious and understandable, specific embodiments of this utility model are given below.

[0040] The above and other objects, advantages and features of this utility model will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description

[0041] 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 scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0042] Figure 1 This is a schematic diagram of a solar cell micro-area property scanning system according to an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the structure of an adjustable transient photoelectric measurement unit according to an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the first direction scanning of a solar cell micro-area property scanning system according to an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the second direction scanning of a solar cell micro-area property scanning system according to an embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of the matrix combination of a solar cell micro-area property scanning system according to an embodiment of the present invention, wherein the two dark areas, one horizontal and one vertical, represent the laser irradiation areas of two steps in the scanning of the first and second directions, and they intersect at one point.

[0047] Figure 6This is a schematic diagram of the matrix data processing method of a solar cell micro-area property scanning system according to an embodiment of the present invention;

[0048] Figure 7 This is a schematic diagram of the transient photocurrent integral value scanning visualization result of a solar cell micro-area property scanning system according to an embodiment of the present invention, wherein the color depth represents the relative intensity of the corresponding value;

[0049] Figure 8 This is a schematic diagram of a one-dimensional laser source according to an embodiment of the present invention;

[0050] Figure 9 This is a flowchart illustrating a method for scanning the properties of a micro-area of ​​a solar cell according to an embodiment of the present invention. Detailed Implementation

[0051] 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.

[0052] As mentioned earlier, although methods for detecting defects and inhomogeneities in solar cells, such as micro-area JV, micro-area fluorescence, or micro-area transient photoelectric measurement, have been proposed, existing micro-area characterization relies on point-by-point scanning. Performing a large number of spatial inhomogeneity scans of solar cells requires a lot of manpower and time, which is detrimental to the advancement of solar cell process optimization.

[0053] Transient photoelectric measurement technology, including transient photocurrent and transient photovoltage measurements, can study the charge dynamics of devices under short-circuit and open-circuit operating states, and thus enable qualitative comparisons between different devices. The inventors of this application have previously developed adjustable transient photoelectric measurement technology, related physical models and data processing methods, as well as an adjustable transient photoelectric measurement system, which can quantitatively analyze the charge loss of solar cells under different operating states. However, although existing systems can provide detailed charge dynamics properties of solar cell devices, the time consumed increases a thousandfold when micro-area spatial scanning is involved, making them unsuitable for batch scanning of the transient photoelectric properties of micro-areas of solar cells.

[0054] To address the aforementioned issues, this utility model proposes an integrated solar cell micro-area property scanning system 100, which can achieve rapid scanning and non-uniformity analysis of solar cell micro-area properties (especially transient photoelectric properties), while significantly reducing the number of samplings required for micro-area scanning.

[0055] Figure 1 This is a schematic block diagram illustrating the functional structure of a solar cell micro-area property scanning system 100 according to an embodiment of the present invention. Straight lines represent circuit or signal connections, thin solid lines extending downwards from the one-dimensional laser source 110 represent laser light, and curly braces indicate that the automatic control and data processing unit is connected to other components by circuits or signals. See also... Figure 1 As shown, in one embodiment, the solar cell micro-area property scanning system 100 of the present invention generally includes a one-dimensional laser light source 110, a sample stage 120, a precision displacement device 130, a micro-area property measurement unit 140, and an automatic control and data processing unit 150.

[0056] The one-dimensional laser source 110 is configured to generate a one-dimensional line scan laser of a specified size and frequency.

[0057] The sample stage 120 is used to hold the solar cell sample to be tested and to connect the solar cell sample to the micro-area property measurement unit 140. The sample stage 120 can also connect the solar cell sample to an adjustable power supply (not shown in the figure).

[0058] The precision displacement device 130 is configured to cause relative movement between the one-dimensional laser source 110 and the sample stage 120, thereby enabling the one-dimensional line-scan laser to scan the measurement area of ​​the solar cell sample, comprising multiple micro-regions, in a cross-scan manner. In some alternative embodiments, the precision displacement device 130 can achieve relative movement between the sample stage 120 and the one-dimensional laser source 110 by driving the sample stage 120 to move. In other alternative embodiments, the precision displacement device 130 can also achieve relative movement between the sample stage 120 and the one-dimensional laser source 110 by driving the one-dimensional laser source 110 to move.

[0059] The micro-area property measurement unit 140 is configured to acquire property data of the scanned area to be measured.

[0060] The automatic control and data processing unit 150 is connected to the one-dimensional laser source 110, the precise displacement device 130, and the micro-area property measurement unit 140, respectively. It is configured to control the operation of the precise displacement device 130 and the one-dimensional laser source 110, and to collect and process property data from the micro-area property measurement unit 140. Specifically, the automatic control and data processing unit 150 extracts property information at the vertical intersections of the cross-scans based on the property data, and determines the distribution of micro-area properties using the property information at the vertical intersections.

[0061] Specifically, the automatic control and data processing unit 150 may include a computer with built-in automatic control programs. The automatic control and data processing unit 150 can control the pulse frequency of the laser emitted by the one-dimensional laser source 110, thereby obtaining property data of the solar cell sample being excited at a suitable frequency. The automatic control and data processing unit 150 can also control the precision displacement device 130 to perform spatial scanning, and can simultaneously record the spatial coordinates of the micro-region.

[0062] The solar cell micro-area property scanning system 100 provided in this embodiment of the invention achieves rapid scanning of the micro-area properties of the solar cell sample by causing relative movement between the one-dimensional laser source 110 and the sample stage 120. This allows the one-dimensional line scanning laser emitted by the laser source to scan multiple micro-areas of the solar cell sample held on the sample stage 120 in a cross-scan manner. The system automatically collects and processes the property data of the micro-areas, extracts property information at the perpendicular intersections of the cross-scans, and determines the distribution of micro-area properties based on this information. By acquiring micro-area information through one-dimensional line laser cross-scanning, the number of steps required for micro-area scanning can be significantly reduced, thereby greatly shortening the scanning time and reducing the number of sampling operations.

[0063] In some embodiments, the properties of the micro-region may include its photoelectric properties and / or fluorescence properties. Accordingly, the micro-region property measurement unit 140 employs a unit capable of measuring and acquiring photoelectric property information and / or fluorescence property information of the solar cell. For example, existing measurement units capable of measuring and acquiring photoelectric property information and / or fluorescence property information of solar cells can be used; those skilled in the art should be familiar with the structure of such measurement units, which will not be described further herein.

[0064] Therefore, the solar cell micro-area property scanning system 100 of this embodiment can not only be used for scanning the photoelectric properties of micro-areas, but also for rapid spatial scanning of properties such as fluorescence in micro-areas, providing a solution for high-throughput scanning in batches.

[0065] In some embodiments, the properties of the micro-region are the transient photoelectric properties of the micro-region. Specifically, the property data collected by the micro-region property measurement unit 140 may include transient photocurrent data and / or transient photovoltage data generated by the solar cell sample under laser excitation.

[0066] Accordingly, the micro-area property measurement unit 140 can be an adjustable transient photoelectric measurement unit 140.

[0067] Figure 2 This is a schematic diagram of the adjustable transient photoelectric measurement unit 140 according to an embodiment of the present invention. See also... Figure 2As 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 sample (fixed on the sample stage 120) to put it in a semiconductor electrical state; a filter module 142 connected between the voltage bias module 141 and the solar cell sample, configured to match the impedance between the measurement circuit of the adjustable transient photoelectric measurement unit 140 and the solar cell sample, so that the voltage bias module 141 applies the specified bias voltage to the solar cell sample; 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 sample and the sampling resistor module 143 respectively, configured to acquire the electrical signal of the solar cell sample under the excitation of a one-dimensional line scanning laser.

[0068] In this embodiment, an adjustable transient photoelectric measurement unit 140 is used to realize rapid scanning and processing of the transient photoelectric properties of the micro-region of the solar cell.

[0069] 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.

[0070] In some specific embodiments, the voltage bias module 141 can provide a bias voltage from -10V to 10V.

[0071] In a further embodiment, the adjustable transient photoelectric measurement unit 140 may further include a function switching module 145 connected between the solar cell sample and the filter module 142, configured to be operable to allow the adjustable transient photoelectric measurement unit 140 to switch between different measurement modes.

[0072] Specifically, different measurement modes can include transient photovoltage measurement mode under no voltage regulation mode, transient photocurrent measurement mode under different voltages, and transient photovoltage measurement mode under different voltages. Through switching via the function switching module 145, the adjustable transient photoelectric measurement unit 140 can measure the transient photovoltage curve under no voltage regulation mode, thereby acquiring the transient photovoltage signal under no voltage regulation mode; or measure the transient photocurrent curve of the solar cell sample under different voltages, thereby acquiring the transient photocurrent signal under different scanning voltages; or measure the transient photovoltage curve of the solar cell sample under different voltages, thereby acquiring the transient photovoltage signal under different scanning voltages. The function switching module 145 can be implemented via a selection switch, such as a manual single-pole three-throw switch or an electromagnetic relay switch.

[0073] 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.

[0074] In some embodiments, the precision displacement device 130 can also be configured to: first, cause the one-dimensional line scanning laser generated by the one-dimensional laser source 110 to perform n steps of scanning along a first direction perpendicular to one side of the area to be measured of the solar cell sample, parallel to one side of the area to be measured, and cover the area to be measured of the solar cell sample; then, cause the one-dimensional line scanning laser generated by the one-dimensional laser source 110 to perform m steps of scanning along a second direction perpendicular to the other side of the area to be measured of the solar cell sample, parallel to the other side of the area to be measured of the solar cell sample, and cover the area to be measured of the solar cell sample, thereby completing the cross-scanning, wherein the other side of the area to be measured of the solar cell sample is perpendicular to one side. Those skilled in the art will understand that a single solar cell and its area to be measured are typically designed as a rectangle, and the one side and the other side can refer to two adjacent sides of the rectangle.

[0075] Figure 3 and Figure 4 The diagrams show scanning schematics of a solar cell micro-area property scanning system 100 according to an embodiment of the present invention in a first direction and a second direction. Figure 3 The vertical direction indicated by the arrow represents the first direction, so scanning in the first direction can also be called vertical scanning. The thick black solid line represents the one-dimensional laser region, which covers the area to be measured of the solar cell sample in a direction parallel to one of its edges. The size of the laser region in the first direction is similar to that of the micro-area; for example, the difference between the size of the one-dimensional laser region in the first direction and the size of the micro-area is ±10% of the micro-area size. The thin arrow represents the one-dimensional laser scanning direction (i.e., the first direction). The one-dimensional laser steps n times in this direction to cover the entire area to be measured.

[0076] Figure 4 The horizontal direction indicated by the arrow represents the second direction, so scanning in the second direction can also be called horizontal scanning. The thick black solid line represents the one-dimensional laser region, which covers the area to be measured of the solar cell sample in a direction parallel to the other side of the sample. The size of the laser region in the second direction is similar to that of the micro-area; for example, the difference between the size of the one-dimensional laser region in the second direction and the size of the micro-area is ±10% of the micro-area size. The thin arrow represents the one-dimensional laser scanning direction (i.e., the second direction). The one-dimensional laser steps m times in this direction to cover the entire area to be measured.

[0077] Optionally, the size, step distance, and number of steps of the one-dimensional laser can be adjusted according to the size of the area to be measured and the accuracy requirements.

[0078] When measuring the photoelectric properties of a solar cell sample under laser light using an adjustable transient photoelectric measurement unit 140, the automatic control and data processing unit 150 is connected to the adjustable transient photoelectric measurement unit 140 (specifically, 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 the electrical signal collected by the adjustable transient photoelectric measurement unit 140 (specifically, the electrical signal measurement module 144 in the adjustable transient photoelectric measurement unit 140) at each step, and coordinate the timing sequence of voltage output by the voltage bias module 141 and signal acquisition by the electrical signal measurement module 144.

[0079] Meanwhile, the automatic control and data processing unit can control the pulse frequency of the one-dimensional laser source 110 to obtain the micro-region transient photoelectric signal of the solar cell sample at a suitable frequency.

[0080] In addition, the automatic control and data processing unit can also collect, process and store the electrical signals generated by the scanned solar cell sample acquired by the adjustable transient photoelectric measurement unit 140 (specifically, the electrical signal measurement module 144 in the adjustable transient photoelectric measurement unit 140).

[0081] In some embodiments, the collected electrical signal is a transient photocurrent signal. The automatic control and data processing unit 150 can also be configured to integrate and extract the transient photocurrent signal collected in each step of the first direction to obtain an n*1 dimensional transient photocurrent integral matrix (e.g., ...). Figure 3 As shown (where the thick arrows represent data processing methods), the transient photocurrent signals acquired in each step of the second direction are integrated and extracted to obtain a 1*m dimensional transient photocurrent integral matrix (e.g., ...). Figure 4 As shown (where the thick arrows represent data processing methods), the n*1 dimensional transient photocurrent integral matrix and the 1*m dimensional transient photocurrent integral matrix are multiplied by rows and columns to obtain the n*m ​​dimensional transient photocurrent integral relative value matrix. The distribution and inhomogeneity of the micro-region transient photoelectric properties of the solar cell sample are determined based on the relative sizes of the matrix elements in the n*m ​​dimensional transient photocurrent integral relative value matrix. The following section combines... Figure 5 and Figure 6 This will explain the data processing method of the automatic control and data processing unit.

[0082] Figure 5 This is a matrix combination schematic diagram of a solar cell micro-area property scanning system 100 according to an embodiment of the present invention, wherein the two dark areas horizontally and vertically represent the laser irradiation areas of two steps in the scanning of the first direction and the second direction, and they intersect at one point vertically. Figure 6This is a schematic diagram of the matrix data processing method of a solar cell micro-area property scanning system 100 according to an embodiment of the present invention.

[0083] As mentioned earlier, the two-step scanning process of the solar cell micro-area property scanning system 100 yielded two matrices representing the spatial distribution of transient photocurrent integral values: an n*1 dimensional and a 1*m dimensional transient photocurrent integral matrix, representing the transient photoelectric properties of each step region. Further processing of these matrices allows for the acquisition of more detailed micro-area information. Figure 5 The illumination regions of the two steps during the first and second direction scanning processes are illustrated exemplarily. The transient photocurrent integral values ​​of these two regions are stored in n*1 and 1*m dimensional matrices, respectively. Since each micro-region is the overlap of two perpendicularly intersecting step regions, the n*m ​​dimensional matrix obtained by multiplying these two matrices by their rows and columns can represent the spatial distribution of the relative values ​​of the transient photocurrent integrals of the micro-region.

[0084] Figure 6 An exemplary data processing method for a solar cell micro-area property scanning system 100 is presented. Each matrix element represents an overlapping micro-area. The n*1 dimensional matrix is ​​multiplied by the 1*m dimensional matrix, and each matrix element is derived from the overlap of the n*1 dimensional matrix and the 1*m dimensional matrix, that is, from the overlap of the signals from two laser steps. The relative size of the matrix element represents the distribution and non-uniformity of the transient photoelectric properties of the micro-area.

[0085] As can be seen, in this embodiment, by stepping a one-dimensional line-scanning laser along two mutually perpendicular directions to scan the area to be measured of the solar cell sample, transient photocurrent information at the perpendicular intersection can be obtained. Integrating the transient photocurrent under each step yields an n*1 dimensional transient photocurrent integral matrix and a 1*m dimensional transient photocurrent integral matrix. Multiplying the two matrices by their rows and columns yields an n*m dimensional transient photocurrent integral relative value matrix. Therefore, the non-uniformity information of the solar cell sample can be obtained based on the relative sizes of the matrix elements in the n*m ​​dimensional transient photocurrent integral relative value matrix, and the distribution of its spatial defects can be located.

[0086] The solar cell micro-area property scanning system 100 provided in this embodiment of the present invention optimizes the micro-area measurement process that requires n*m steps to n+m steps through the above scanning and data processing methods. It uses the information at the perpendicular intersection to represent the micro-area information. While preserving the transient photoelectric property distribution information of the micro-area, it greatly saves scanning time and reduces the number of samplings, and can realize rapid and large-scale non-uniformity detection of solar cells.

[0087] Figure 7This is a schematic diagram of the transient photocurrent integral value scanning visualization results of a solar cell micro-area property scanning system 100 under a specific bias voltage according to an embodiment of the present invention, where the color depth represents the relative intensity of the corresponding value. Figure 7 As can be seen, based on the above scanning process and data processing, the automatic control and data processing unit 150 can visualize the relative magnitude of the transient photocurrent integral values ​​of each micro-region. In some embodiments, the relative magnitude of the transient photocurrent integral is represented by grayscale, with a higher grayscale value indicating a larger value.

[0088] In order to accurately locate the defect, in some specific embodiments, the properties of the micro-region can be determined based on the relative magnitude of the transient photocurrent integral, and the quality of the indicated region can be quantitatively calibrated.

[0089] The solar cell micro-area property scanning system 100 provided in this embodiment of the present invention can quickly complete the spatial scanning of the photoelectric properties of the micro-area of ​​solar cells through the above scanning method and data processing, visualize the magnitude of the integral value of transient photocurrent in the micro-area, significantly reduce the number of samplings required for micro-area scanning, and provide a powerful tool for batch detection of spatial defect distribution and non-uniformity of solar cells.

[0090] As previously described, the one-dimensional laser source 110 is configured to generate a one-dimensional line-scanning laser (line pulse laser) of a specified size and frequency and apply it to the solar cell sample to excite the linear region to undergo processes related to the properties of the micro-region to be measured (such as fluorescence processes, transient photoelectric processes, etc.).

[0091] Figure 8 This is a schematic diagram of a one-dimensional laser source 110 according to an embodiment of the present invention, wherein arrows indicate the direction of the optical path. See also... Figure 8 As shown, in some embodiments, the one-dimensional laser source 110 may include: a laser attenuator 111 for adjusting the intensity of the laser; a cylindrical lens 112 disposed downstream of the optical path of the laser attenuator 111 for converting the incident laser into a one-dimensional line laser of a specific size; and an adjustable aperture 113 disposed downstream of the optical path of the cylindrical lens 112 for adjusting the size of the one-dimensional line laser. Of course, those skilled in the art will understand that the one-dimensional laser source 110 may also include a laser located upstream of the laser attenuator 111 to generate laser light.

[0092] The sample stage 120 is used to fix a solar cell sample and connect it to the measurement circuit of the micro-area property measurement unit 140. In some embodiments, the sample stage 120 includes: an adjustable clamp configured to be adjustable according to the size of the solar cell sample to be tested, so as to fix solar cell samples of different sizes; and a probe for contacting the electrodes of the solar cell sample and connecting the solar cell sample to the micro-area property measurement unit 140.

[0093] In one specific embodiment, the adjustable clamp may be a magnetic clamp. Those skilled in the art will understand the working principle of magnetic clamps, which will not be described in detail here.

[0094] As mentioned earlier, the precision displacement device 130 can move the sample stage 120 or the one-dimensional laser source 110 to achieve relative movement between them.

[0095] See Figure 1 In some optional embodiments, the precision displacement device 130 may include: a displacement stage 131 for supporting the sample stage 120; a displacement track 132 for supporting the displacement stage 131 and allowing the displacement stage 131 to drive the sample stage 120 to move along the displacement track 132 in two-dimensional xy-degrees of freedom; and a driving element (not shown) for driving the displacement stage 131 to move along the displacement track 132. Through the displacement stage 131 and the displacement track 132, micrometer-level spatial scanning in both x and y directions can be achieved. The x and y directions can be parallel to one side and the other side of the area to be measured of the solar cell sample, respectively.

[0096] In a further embodiment, the displacement track 132 may include an x-axis lead screw and a y-axis lead screw. The driving elements may include two motors that drive the x-axis and y-axis lead screws respectively, both of which are connected to the automatic control and data processing unit 150. Thus, under the control of the automatic control and data processing unit 150, the motors drive the lead screws, thereby causing the displacement stage 131 to move precisely to achieve cross-scanning.

[0097] In some embodiments, the automatic control and data processing unit 150 is connected to the one-dimensional laser source 110, the driving element (such as a motor) in the precision displacement device 130, and the adjustable transient photoelectric measurement unit 140, and is configured to: control the pulse frequency of the one-dimensional laser source 110; control the spatial position of the displacement stage 131 and control the displacement stage 131 to move to achieve spatial scanning; and acquire the transient photoelectric signal output by the adjustable transient photoelectric measurement unit 140.

[0098] In some specific embodiments, the automatic control and data processing unit 150 can be a computer with a built-in automated control program, which controls the coordinated operation of various components and modules by running the automated program. The control of the automatic control and data processing unit 150 mainly includes: controlling the pulse frequency of the one-dimensional laser source 110; recording the spatial position of the displacement stage 131 and controlling the precise movement of the displacement stage 131 for spatial scanning; controlling the operating voltage provided by the adjustable transient photoelectric measurement unit 140, switching the operating mode of the adjustable transient photoelectric measurement unit 140, and acquiring the transient photoelectric signals output by the adjustable transient photoelectric measurement unit 140; and analyzing and visualizing the scanning data output by the adjustable transient photoelectric measurement unit 140. The acquisition, analysis, and visualization of the transient photoelectric signals have been described above and will not be repeated here.

[0099] The solar cell micro-area property scanning system 100 provided in this embodiment can be used to rapidly scan the transient photoelectric properties of solar cell micro-areas and automatically scan and measure the charge dynamics process of micro-areas under different bias voltages and illumination conditions, so as to measure and analyze the micro-area properties and inhomogeneities 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 saving the manpower and time required for spatial scanning of micro-area photoelectric properties.

[0100] Based on the same technical concept, this utility model also provides a method for scanning the properties of a micro-area of ​​a solar cell. This scanning method can be performed based on the aforementioned solar cell micro-area property scanning system 100.

[0101] Figure 9 This is a schematic flowchart illustrating a method for scanning the properties of a micro-area of ​​a solar cell according to an embodiment of the present invention. See also... Figure 9 As shown, the method for scanning the properties of a solar cell microarea includes at least the following steps S902 to S908.

[0102] In step S902, after clamping the solar cell sample to be tested on the sample stage 120 and connecting it to the micro-area property measurement unit 140, the one-dimensional laser source 110 is controlled to generate a one-dimensional line scanning laser of a specified size and frequency.

[0103] Specifically, in step S902, a one-dimensional laser source 110 is set to output pulsed laser at a specific frequency, and the size of the pulsed laser is adjusted to suit the measurement area of ​​the solar cell sample.

[0104] Step S904: The one-dimensional laser source 110 and the sample stage 120 are moved relative to each other so that the one-dimensional line scanning laser scans the measurement area of ​​the solar cell sample, which includes multiple micro-regions, in a cross-scanning manner.

[0105] Step S906: Control the micro-area property measurement unit 140 to collect property data of the scanned area to be measured.

[0106] Step S908: Collect property data from the micro-area property measurement unit 140, extract the relative property value information at the vertical intersection of the cross scan based on the property data, and determine the distribution of micro-area properties based on the relative property value information at the vertical intersection.

[0107] Specifically, the aforementioned steps S902 to S908 can be executed by the automatic control and data processing unit 150 of the solar cell micro-area property scanning system 100.

[0108] Before performing step S902, the solar cell sample to be tested is fixed on the sample stage 120 and connected to the measurement circuit of the micro-area property measurement unit 140 with a probe.

[0109] In some embodiments, the properties of the microregion include photoelectric properties and / or fluorescence properties.

[0110] In some embodiments, step S904 may specifically include:

[0111] First, the one-dimensional line scanning laser generated by the one-dimensional laser source 110 scans n times along a first direction perpendicular to one side of the solar cell sample while parallel to one side of the sample, covering the area to be measured of the solar cell sample. Then, the one-dimensional line scanning laser generated by the one-dimensional laser source 110 scans m times along a second direction perpendicular to the other side of the solar cell sample while parallel to the other side of the sample, covering the area to be measured of the solar cell sample, thus completing the cross-scan. The other side of the solar cell sample is perpendicular to the first side.

[0112] In a specific embodiment, step S904 can be specifically implemented as follows:

[0113] Rotate the one-dimensional laser source 110 so that the line scanning laser emitted by it is parallel to one side of the area to be measured of the solar cell sample and is located at the beginning of the area to be measured.

[0114] The displacement stage 131 is moved to make the line scanning laser step n times in the first direction and cover the area to be measured.

[0115] Adjust the one-dimensional laser source 110 so that the emitted line scanning laser is parallel to the other side of the area to be measured and is located at the beginning of the area to be measured;

[0116] The displacement stage 131 is controlled to move, so that the line scanning laser steps m times in the second direction and covers the area to be measured.

[0117] In some further embodiments, the properties of the micro-region are the transient photoelectric properties of the micro-region.

[0118] Step S906 may specifically include:

[0119] The micro-area property measurement unit 140 controls the acquisition of transient photocurrent signals at each step.

[0120] Step S908 may specifically include:

[0121] The transient photocurrent signals acquired in each step of the first direction are integrated and extracted to obtain an n*1 dimensional transient photocurrent integral matrix. The transient photocurrent signals acquired in each step of the second direction are integrated and extracted to obtain a 1*m dimensional transient photocurrent integral matrix. The n*1 dimensional transient photocurrent integral matrix and the 1*m dimensional transient photocurrent integral matrix are multiplied by rows and columns to obtain an n*m dimensional transient photocurrent integral relative value matrix. The distribution and non-uniformity of the micro-region transient photoelectric properties of the solar cell sample are determined based on the relative size of the matrix elements in the n*m ​​dimensional transient photocurrent integral relative value matrix.

[0122] The solar cell micro-area property scanning method provided in this embodiment combines one-dimensional laser scanning with micro-area transient photoelectric measurement. A line laser of a specific size is used to perform bidirectional two-dimensional scanning of the cell under test. The matrix representing the micro-area properties is obtained by multiplying the two transient photocurrent integral value matrices.

[0123] Furthermore, by analyzing the obtained matrix, the non-uniformity information of the solar cell can be obtained, and the distribution of its spatial defects can be located. This method significantly reduces the number of samplings required for micro-area scanning, making it possible to perform rapid spatial scanning of the photoelectric properties of solar cell micro-areas and batch uniformity analysis.

[0124] 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.

[0125] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the present 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.

[0126] Therefore, those skilled in the art should recognize that although many 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 present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A micro-area property scanning system for solar cells, characterized in that, include: A one-dimensional laser source configured to generate a one-dimensional line scan laser of a specified size and frequency; A sample stage is used to hold the solar cell sample to be tested and to connect the solar cell sample to the micro-area property measurement unit; A precision displacement device is configured to cause relative movement between the one-dimensional laser source and the sample stage, so that the one-dimensional line scanning laser scans the measurable region of the solar cell sample, which includes multiple micro-regions, in a cross-scan manner. The micro-area property measurement unit is configured to acquire property data of the scanned area to be measured; as well as An automatic control and data processing unit is connected to the one-dimensional laser source, the precise displacement device, and the micro-area property measurement unit, respectively. It is configured to control the operation of the precise displacement device and the one-dimensional laser source, collect property data from the micro-area property measurement unit, extract property information at the vertical intersection of the cross-scan based on the property data, and determine the distribution of micro-area properties based on the property information at the vertical intersection.

2. The solar cell micro-area property scanning system according to claim 1, 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 is used to drive the displacement stage to move along the displacement track.

3. The solar cell micro-area property scanning system according to claim 2, characterized in that, The displacement track includes an x-axis lead screw and a y-axis lead screw; The driving element includes two motors that drive the x-axis lead screw and the y-axis lead screw respectively, and both motors are connected to the automatic control and data processing unit.

4. The solar cell micro-area property scanning system according to claim 1, characterized in that, The sample stage includes: An adjustable clamp, configured to be adjustable according to the size of the solar cell sample to be tested, to fix solar cell samples of different sizes to be tested; and A probe is used to contact the electrodes of the solar cell sample and connect the solar cell sample to the micro-area property measurement unit.

5. The solar cell micro-area property scanning system according to claim 4, characterized in that, The adjustable clamp is a magnetic clamp.

6. The solar cell micro-area property scanning system according to claim 1, characterized in that, The one-dimensional laser source includes: Laser attenuator, used to adjust the intensity of the laser; A cylindrical lens, positioned downstream of the laser attenuator, is used to convert the incident laser into a one-dimensional line laser of a specific size; and An adjustable aperture is located downstream of the cylindrical lens in the optical path and is used to adjust the size of the one-dimensional line laser.

7. The solar cell micro-area property scanning system according to claim 1, characterized in that, The micro-area property measurement unit is an adjustable transient photoelectric measurement unit.

8. The solar cell micro-area property scanning system according to claim 7, characterized in that, The adjustable transient photoelectric measurement unit includes: A voltage bias module is configured to apply a specified bias voltage to the solar cell sample to place it in a semiconductor electrical state. A filter module, connected between the voltage bias module and the solar cell sample, is configured to impedance match between the measurement circuit of the adjustable transient photoelectric measurement unit and the solar cell sample, so that the voltage bias module applies the specified bias voltage to the solar cell sample. A sampling resistor module is connected in parallel across the filter module and the voltage bias module; and An electrical signal measurement module is connected to both the solar cell sample and the sampling resistor module, and is configured to acquire the electrical signal of the solar cell sample under the excitation of the one-dimensional line scanning laser.

9. The solar cell micro-area property scanning system according to claim 8, characterized in that, The adjustable transient photoelectric measurement unit also includes: A function switching module, connected between the solar cell sample and the filter module, is configured to be operable to allow the adjustable transient photoelectric measurement unit to switch between different measurement modes.

10. The solar cell micro-area property scanning system according to claim 1, characterized in that, The automatic control and data processing unit includes a computer with built-in automatic control programs.

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