Method, system and device for characterizing the edge loss of a crystalline silicon solar cell slice

Abstract

The present application relates to the technical field of solar cell loss characterization, in particular to a method, system and device for characterizing edge loss of a sliced crystalline silicon solar cell, the method comprising: slicing a crystalline silicon solar cell along a crystal plane into a plurality of sub-cells with different areas, and placing the plurality of sub-cells in an open circuit state; exciting carriers in each sub-cell at different positions to obtain a plurality of small perturbation transient photovoltage; obtaining carrier lifetimes of the plurality of sub-cells based on the plurality of small perturbation transient photovoltage; and obtaining an evaluation result of edge damage degree of the sliced sub-cells according to the carrier lifetimes of the plurality of sub-cells. The present application uses small optical perturbation for non-destructive testing, and measures small perturbation transient photovoltage at different positions, so that the influence of edge damage caused in the slicing process on the performance of the cell can be accurately captured, and the edge loss degree can be accurately evaluated.

Description

Technical Field

[0001] This invention relates to the field of solar cell loss characterization technology, and in particular to methods, systems and apparatus for characterizing edge loss after slicing crystalline silicon solar cells. Background Technology

[0002] Photovoltaic technology is the most promising technology for obtaining clean and renewable energy. Crystalline silicon (c-Si) solar cells maintain their dominant position in the industry due to their mature technology and significant market share (over 95%). In recent years, photovoltaic technology has undergone rapid iterations, gradually transitioning from traditional aluminum back field cells (Al-BSF) to high-efficiency passivated emitter stage and PERC (Performance-Reverse Contact) technology. By the end of 2020, PERC technology had captured over 80% of the market share, and together with half-cell module technology, it has significantly reduced power consumption, increased system power output, and enabled large-scale commercial applications.

[0003] However, as the efficiency of PERC technology approaches its theoretical limit, the research focus in the photovoltaic field has shifted to next-generation high-efficiency cell technologies, such as tunneling oxide passivated contacts (TOPCon) and silicon heterojunction (SHJ) cells. These novel passivation contact technologies have successfully boosted photoelectric conversion efficiency to over 26% by further reducing recombination losses in crystalline silicon solar cells, ushering in a new era for photovoltaic efficiency.

[0004] To further improve the power density and efficiency of battery modules, the industry is actively exploring strategies to cut large-size solar panels into smaller sub-cell units. Through laser cutting technology, the entire cell is precisely divided into parts with an area of ​​1 / 2, 1 / 3, 1 / 4, or even smaller than the original panel, thereby achieving higher power output within a limited space and reducing energy loss between the cell and the module. However, the unpassivated cutting edges generated in this process have become a key factor affecting the overall efficiency of the device, as they induce additional recombination losses.

[0005] Therefore, optimizing the cutting process to create a smoother cutting interface, implementing effective edge passivation measures, and developing precise characterization methods to visualize edge loss have become current hot topics and challenges in photovoltaic technology research. Given the relatively weak research in edge loss characterization, the industry generally relies on photovoltaic electroluminescence (EL) technology to monitor the yield rate of production lines, but this is far from sufficient to fully reveal the edge loss mechanism of devices after slicing. Therefore, developing and applying advanced characterization techniques to visually demonstrate edge loss and deeply analyze the underlying physical mechanisms is of great significance for promoting the continuous progress of photovoltaic cell technology and large-scale, efficient production. Summary of the Invention

[0006] Therefore, the technical problem to be solved by this invention is: how to effectively reduce the recombination loss at the unpassivated cutting edge after slicing crystalline silicon solar cells, and accurately quantify and visualize the edge loss, so as to improve the overall efficiency of the cell.

[0007] To address the aforementioned technical problems, this invention provides a method for characterizing the edge loss of crystalline silicon solar cells after slicing, comprising the following steps:

[0008] S1: Cut the crystalline silicon solar cell into multiple sub-cells of different sizes along the crystal plane, and put the multiple sub-cells in an open circuit state. Excite the carriers in each sub-cell at different locations to obtain multiple small perturbation transient photovoltages.

[0009] S2: Based on the multiple small-perturbation transient photovoltages, the carrier lifetime of multiple sub-cells is obtained;

[0010] S3: Based on the carrier lifetime of the multiple sub-cells, obtain the evaluation result of the edge damage degree of the sub-cells after slicing.

[0011] In one embodiment of the present invention, in S1, the method for obtaining multiple small-perturbation transient photovoltages is as follows:

[0012] For each sub-cell, a small optical perturbation is used to move from the edge of each sub-cell inward to obtain the small perturbation transient photovoltage and the saturation voltage of the small perturbation transient photovoltage at different distances from the edge cutting surface.

[0013] In one embodiment of the present invention, in S2, the method for obtaining the carrier lifetime of multiple sub-cells is as follows:

[0014] S21: Based on the multiple small perturbation transient photovoltages, a transient photovoltage spectrum is obtained;

[0015] S22: Based on the fitting expression of the carrier lifetime, fit the transient photovoltage spectrum to obtain the carrier lifetime of multiple sub-cells.

[0016] In one embodiment of the present invention, the fitted expression for the carrier lifetime τ is:

[0017]

[0018] Wherein, ΔV(t) is the transient photovoltage at the corresponding time point t during the test, and ΔV0 is the saturation value of the small-disturbance transient photovoltage ΔV.

[0019] In one embodiment of the present invention, in S3, the method for obtaining the evaluation result of the edge damage degree of the sliced ​​sub-cell includes: obtaining the carrier recombination degree of different regions of the sliced ​​sub-cell based on the carrier lifetime of the plurality of sub-cells, and obtaining the evaluation result of the edge damage degree of the sliced ​​sub-cell based on the carrier recombination degree.

[0020] In one embodiment of the present invention, in S1, the method of putting the plurality of sub-cells in an open-circuit state is: to irradiate the plurality of sub-cells with a white light source.

[0021] The present invention also provides a control system for implementing the steps of the above-described method for characterizing the edge loss of crystalline silicon solar cells after slicing, the control system comprising the following modules:

[0022] The transient photovoltage acquisition module is used to cut a crystalline silicon solar cell into multiple sub-cells of different area sizes along the crystal plane, and to put the multiple sub-cells in an open circuit state, to excite the charge carriers in each sub-cell at different locations, and to acquire multiple small perturbation transient photovoltages.

[0023] The carrier lifetime calculation module is used to obtain the carrier lifetime of multiple sub-cells based on the multiple small perturbation transient photovoltages;

[0024] The damage assessment module is used to obtain the assessment result of the edge damage of the sub-cells after slicing based on the carrier lifetime of the multiple sub-cells.

[0025] The present invention also provides a characterization device for edge loss of crystalline silicon solar cells after slicing, including the control system and the small perturbation transient photovoltage testing device; wherein, the small perturbation transient photovoltage testing device acquires multiple small perturbation transient photovoltages in different regions of the sliced ​​sub-cell when open-circuited, the control system performs fitting calculations based on the multiple small perturbation transient photovoltages to obtain the carrier lifetime, and evaluates the degree of edge loss of the cell based on the carrier lifetime.

[0026] In one embodiment of the present invention, the small-disturbance transient photovoltage testing device includes a function signal generator, an oscilloscope, a pulsed laser, and a light source device;

[0027] The function signal generator is connected to the oscilloscope and the pulsed laser. The oscilloscope is connected to each sliced ​​sub-cell. The light source device illuminates each sliced ​​sub-cell to make it open-circuit. The pulsed laser provides small optical perturbations. The small optical perturbations are moved along the edge of the cell's cut surface inward. The oscilloscope acquires the small perturbation transient photovoltage at different locations.

[0028] In one embodiment of the present invention, the light source device provides a white light source.

[0029] The technical solution of the present invention has the following advantages compared with the prior art:

[0030] 1. Accurate characterization of edge loss: By measuring the transient photovoltage (TPV) with small perturbations at different locations, this technology can accurately capture the impact of edge damage caused during the slicing process on battery performance, and thus accurately assess the degree of edge loss.

[0031] 2. Non-destructive testing: This method uses small optical perturbations for non-destructive testing, which will not cause physical or chemical damage to the solar cell, ensuring that the battery can still be used or further analyzed after testing.

[0032] 3. Multi-region analysis: By moving small optical perturbations inward along the cut edge of the battery, TPV data at different locations can be obtained, thereby analyzing the carrier recombination degree and edge damage in different regions of the battery after slicing, providing a comprehensive damage assessment. Attached Figure Description

[0033] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0034] Figure 1 This is a flowchart of a method for characterizing edge loss of a crystalline silicon solar cell after slicing, as provided in Embodiment 1 of the present invention.

[0035] Figure 2 This is a flowchart of the method for obtaining the carrier lifetime of multiple sub-cells provided in Embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic diagram of a control system structure provided in Embodiment 2 of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure of the characterization device for edge loss of crystalline silicon solar cells after slicing, provided in Embodiment 3 of the present invention;

[0038] Figure 5 yes Figure 3 A schematic diagram of the structure of the small-perturbation transient photovoltage testing device;

[0039] Figure 6 (a) represents a distance of 1×1cm. 2 The inset shows the fitting analysis of the small-perturbation transient photovoltage (TPV) spectrum and carrier lifetime τ at different distances d at the edge cut surface of the SHJ battery under 520nm laser and white light. (b) indicates the distance area of ​​1×1cm. 2The carrier lifetime τ and photovoltage saturation curves ΔV0 at different distances d at the edge cut surface of the SHJ battery under 520nm laser and white light.

[0040] Explanation of reference numerals in the accompanying drawings: 100, Transient photovoltage acquisition module; 200, Carrier lifetime calculation module; 300, Damage assessment module; 10, Control system; 20, Small disturbance transient photovoltage testing device; 201, Function signal generator; 202, Oscilloscope; 203, Pulsed laser; 204, Light source equipment. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0042] Example 1

[0043] Reference Figure 1 As shown, this invention provides a method for characterizing edge loss after slicing a crystalline silicon solar cell, comprising the following steps:

[0044] S1: The crystalline silicon solar cell is cut into multiple sub-cells of different sizes along the crystal plane, and the multiple sub-cells are irradiated with a white light source to make the multiple sub-cells open circuit. The carriers in each sub-cell are excited at different positions to obtain multiple small perturbation transient photovoltages.

[0045] S2: Based on the multiple small-perturbation transient photovoltages, the carrier lifetime of multiple sub-cells is obtained;

[0046] S3: Based on the carrier lifetime of the multiple sub-cells, obtain the evaluation result of the edge damage degree of the sub-cells after slicing.

[0047] As can be seen from the above technical solution, this invention, by exciting charge carriers in the sub-cell at different locations and measuring the transient photovoltage under small perturbations, can accurately capture the impact of edge damage that may occur during the slicing process on charge carrier lifetime. Charge carrier lifetime is one of the important indicators for evaluating solar cell performance; therefore, this method can achieve high-precision evaluation of edge losses. Furthermore, the entire testing process is conducted in an open-circuit state, eliminating the need for physical damage to the solar cell or contact measurements, thus avoiding any additional damage that may be introduced during the testing process and ensuring the accuracy and reliability of the test.

[0048] Furthermore, in S1, the method for obtaining multiple small-perturbation transient photovoltages is as follows:

[0049] For each sub-cell, a small optical perturbation is used as the excitation source. Starting from the edge cut surface of each sub-cell, a precisely controlled optical pulse or beam moves gradually inward along a predetermined path to acquire the transient photovoltage and its saturation voltage at different distances from the edge cut surface. In this process, the small optical perturbation effectively excites the dynamic response of charge carriers inside the sub-cell, thereby generating an observable transient photovoltage signal.

[0050] To comprehensively capture this dynamic process, not only were the instantaneous values ​​of the transient photovoltage with small perturbations recorded at multiple locations at different distances from the edge cutting surface, but special attention was also paid to the saturation state of the photovoltage signal at each location, i.e., the saturation voltage of the transient photovoltage with small perturbations. Obtaining this parameter is crucial for a deeper understanding of the recombination and transport mechanisms of charge carriers in different regions, and also provides key data support for the accurate calculation of subsequent charge carrier lifetimes.

[0051] like Figure 2 As shown in Figure S2, the method for obtaining the carrier lifetime of multiple sub-cells based on the multiple small-perturbation transient photovoltages is as follows:

[0052] S21: Based on the multiple small perturbation transient photovoltages, a transient photovoltage spectrum is obtained;

[0053] S22: Based on the fitting expression of the carrier lifetime, fit the transient photovoltage spectrum to obtain the carrier lifetime of multiple sub-cells.

[0054]

[0055] Wherein, ΔV(t) is the transient photovoltage at the corresponding time point t during the test, and ΔV0 is the saturation value of the small-disturbance transient photovoltage ΔV.

[0056] Furthermore, in S3, the method for obtaining the evaluation result of the edge damage degree of the sub-cells after slicing based on the carrier lifetime of the multiple sub-cells is as follows:

[0057] In solar cells, carrier recombination is mainly classified into two types: direct recombination (such as radiative recombination) and indirect recombination (such as Shockley-Read-Hall recombination, Auger recombination, etc.). Edge damage often leads to an increase in defect states, which in turn promotes indirect recombination and reduces carrier lifetime. Therefore, by comparing the differences in carrier lifetime in different regions of the multiple sub-cells, the analysis results of the degree of carrier recombination in the edge region and the inner region can be obtained.

[0058] Based on the analysis of carrier recombination levels in different regions, an assessment of the edge damage degree of the sub-cells after slicing was obtained. This assessment not only reflects the performance degradation of the edge region relative to the inner region, but also provides important reference for improving the manufacturing process of solar cells. For example, if severe edge damage is found, it may be necessary to adjust the slicing process parameters, optimize edge passivation technology, or adopt more advanced encapsulation protection measures to reduce damage.

[0059] Example 2

[0060] The present invention also provides a control system for implementing the steps of the method for characterizing the edge loss of crystalline silicon solar cells after slicing as described in Embodiment 1. Figure 3 As shown, the control system includes the following modules:

[0061] Transient photovoltage acquisition module 100 is used to cut a crystalline silicon solar cell into multiple sub-cells of different area sizes along the crystal plane, and to put the multiple sub-cells in an open circuit state, to excite the charge carriers in each sub-cell at different locations, and to acquire multiple small perturbation transient photovoltages.

[0062] The carrier lifetime calculation module 200 is used to obtain the carrier lifetime of multiple sub-cells based on the multiple small perturbation transient photovoltages.

[0063] The damage assessment module 300 is used to obtain the assessment result of the edge damage of the sub-cells after slicing based on the carrier lifetime of the multiple sub-cells.

[0064] This embodiment proposes a control system for implementing the aforementioned method for characterizing the edge loss of crystalline silicon solar cells after slicing. Therefore, the specific implementation of the control system can be found in the embodiment section of the aforementioned method for characterizing the edge loss of crystalline silicon solar cells after slicing. For example, the transient photovoltage acquisition module 100, the carrier lifetime calculation module 200, and the damage degree assessment module 300 are respectively used to implement steps S1, S2, and S3 in the method for characterizing the edge loss of crystalline silicon solar cells after slicing in Embodiment 1. Therefore, its specific implementation can be referred to the description of the corresponding embodiments. To avoid redundancy, it will not be repeated here.

[0065] Example 3

[0066] like Figure 4As shown, the present invention also provides a characterization device for edge loss of crystalline silicon solar cells after slicing, including the control system 10 and the small perturbation transient photovoltage testing device 20 described in Embodiment 2; wherein, the small perturbation transient photovoltage testing device 20 acquires multiple small perturbation transient photovoltages in different regions of the sliced ​​sub-cell when it is open-circuited, the control system 10 performs fitting calculations based on the multiple small perturbation transient photovoltages to obtain the carrier lifetime, and evaluates the degree of edge loss of the cell based on the carrier lifetime.

[0067] Furthermore, such as Figure 5 As shown, the small-disturbance transient photovoltage testing device 20 includes a function signal generator 201, an oscilloscope 202, a pulsed laser 203, and a light source device 204;

[0068] The function signal generator 201 is connected to the oscilloscope 202 and is used to send a trigger signal to the oscilloscope 202 to ensure that the oscilloscope 202 captures and records the transient photovoltage signal from the sub-cell at the correct time. This triggering and synchronization mechanism helps ensure the accuracy and consistency of the data. The function signal generator 201 can also generate signals to control the operation of the oscilloscope 202, such as setting parameters like the oscilloscope 202's sampling rate and trigger level, to optimize the capture and processing of the transient photovoltage signal.

[0069] Furthermore, the function signal generator 201 is connected to the pulsed laser 203. The control signal generated by the function signal generator 201 is used to control the operation of the pulsed laser 203, including parameters such as pulse generation, frequency, and pulse width. This ensures that the pulsed laser 203 can output small optical perturbations according to a predetermined timing and characteristics to excite carriers in the sub-cell and generate transient photovoltage signals. Crucially, the precise control of the function signal generator 201 ensures that each pulse output by the pulsed laser 201 is seamlessly synchronized with the sampling operation of the oscilloscope 202. This synchronization is indispensable for capturing and analyzing transient photovoltage signals with extremely short timescales and high sensitivity. It greatly improves the accuracy and reliability of the test, enabling a more precise assessment of the edge loss after slicing crystalline silicon solar cells.

[0070] The oscilloscope 202 is connected to each sliced ​​sub-cell. The light source device 204 provides a white light source to illuminate all the sliced ​​sub-cells, putting them in an open-circuit state. The pulsed laser 203 provides a small optical perturbation. The small optical perturbation is used to move along the edge of the cell's cut surface inward. The oscilloscope 202 acquires the small perturbation transient photovoltage at different locations.

[0071] The performance of the characterization method, system, and apparatus for edge loss after slicing crystalline silicon solar cells proposed in this invention is further verified through experiments below. The finished SHJ solar cells were sliced ​​along the crystal plane into pieces with an area of ​​1×1cm. 2 Sub-battery.

[0072] The area is 1×1cm 2 The TPV curves of the SHJ sub-cell at different distances from the edge were tested using TPV. Under white light illumination, the device was in an open-circuit state. Subsequently, under perturbation provided by a small-pulse laser, the oscilloscope 202 displayed the TPV curve of the device under small optical perturbation. The curve was then fitted to obtain the carrier lifetime τ, which can be used to monitor the degree of carrier recombination in solar cells.

[0073] like Figure 6 As shown in (a), the saturation value ΔV0 of the photogenerated voltage at the edge (d≈61μm) of the SHJ is the smallest. According to formula (1), the τ values ​​at different distances from the edge cutting surface can be calculated to be 240.5μs (d≈61μm), 248.1μs (d≈122μm), and 286.3μs (d≈366μm). Furthermore, as... Figure 6 As shown in (b), τ increases with the distance from the edge cutting surface. These results indicate that severe recombination of charge carriers occurs at the edge due to the cutting loss of the SHJ.

[0074] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0075] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0076] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0077] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0078] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for characterizing edge loss after slicing a crystalline silicon solar cell, characterized in that, The method comprises the following steps: S1: cutting a crystalline silicon solar cell into a plurality of sub-cells with different sizes along the crystal surface, and placing the plurality of sub-cells in an open circuit state, exciting carriers in each sub-cell at different positions, and obtaining a plurality of small perturbation transient photovoltage; S2: obtaining the carrier lifetime of the plurality of sub-cells based on the plurality of small perturbation transient photovoltage, which comprises the following steps: S21: obtaining a transient photovoltage map based on the plurality of small perturbation transient photovoltage; S22: fitting the carrier lifetime according to the fitted expression of the carrier lifetime S3: obtaining an evaluation result of the edge damage degree of the sliced sub-cell based on the carrier lifetime of the plurality of sub-cells. S22: fitting the carrier lifetime according to the fitted expression of the carrier lifetime​ wherein, is the transient photovoltage at the corresponding time point during the test t is the small perturbation transient photovoltage saturation value;​ In S1, the method for obtaining a plurality of small perturbation transient photovoltage is as follows:

2. The method of claim 1, wherein the method is characterized by, For each sub-cell, a small optical perturbation is used to move from the edge to the inside of each sub-cell, and the small perturbation transient photovoltage and the saturation voltage of the small perturbation transient photovoltage at different distances from the edge cutting surface are obtained. In S3, the method for obtaining an evaluation result of the edge damage degree of the sliced sub-cell comprises: obtaining the carrier recombination degree of different regions of the sliced sub-cell based on the carrier lifetime of the plurality of sub-cells, and obtaining an evaluation result of the edge damage degree of the sliced sub-cell based on the carrier recombination degree.

3. The method of claim 1, wherein the method further comprises: In S1, the method for placing the plurality of sub-cells in an open circuit state is to irradiate the plurality of sub-cells with a white light source.

4. The method of claim 1, wherein the method further comprises: determining the thickness of the silicon wafer; and determining the thickness of the kerf loss. The control system comprises the following modules for implementing the steps of the method for characterizing the edge loss of a sliced crystalline silicon solar cell according to any one of claims 1-4:

5. A control system characterized by, A transient photovoltage acquisition module is configured to cut a crystalline silicon solar cell into a plurality of sub-cells with different sizes along the crystal surface, place the plurality of sub-cells in an open circuit state, excite carriers in each sub-cell at different positions, and obtain a plurality of small perturbation transient photovoltage. A carrier lifetime calculation module is configured to obtain the carrier lifetime of the plurality of sub-cells based on the plurality of small perturbation transient photovoltage. A damage degree evaluation module is configured to obtain an evaluation result of the edge damage degree of the sliced sub-cell based on the carrier lifetime of the plurality of sub-cells. The control system and the small perturbation transient photovoltage testing device according to claim 5 are included.

6. A device for characterizing edge loss after slicing a crystalline silicon solar cell, characterized in that, The small perturbation transient photovoltage testing device is configured to obtain a plurality of small perturbation transient photovoltage of different regions of the sliced sub-cell in an open circuit state, and the control system is configured to perform fitting calculation based on the plurality of small perturbation transient photovoltage to obtain the carrier lifetime, and evaluate the edge loss degree of the cell based on the carrier lifetime. The small perturbation transient photovoltage testing device comprises a function signal generator, an oscilloscope, a pulse laser, and a light source device.

7. The apparatus for characterizing kerf loss of a crystalline silicon solar cell according to claim 6, wherein The function signal generator is connected to the oscilloscope and the pulse laser, respectively, the oscilloscope is connected to each sliced sub-cell, the light source device is used to irradiate each sliced sub-cell to place it in an open circuit state, the pulse laser provides a small optical perturbation, and the small optical perturbation is used to move from the edge of the cutting surface of the cell to its inside, and the oscilloscope obtains the small perturbation transient photovoltage at different positions. The light source device provides a white light source.

8. The apparatus for characterizing kerf loss at the rear edge of a crystalline silicon solar cell according to claim 7, wherein: ​

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