A processing method for solar cell, solar cell and photovoltaic module

Abstract

The embodiments of the present application relate to the photovoltaic field and provide a method for processing a solar cell, a solar cell and a photovoltaic module. The processing method includes: performing laser etching on a first area of ​​a substrate, and a second area adjacent to the first area is a damaged area. Obtaining the width of the second area. Determine whether the width of the second area is within a predetermined width range. When the width of the second area is within the predetermined width range, the parameters of the laser etching are recorded as qualified parameters, and the qualified parameters are used to process the cell. When the width of the second area is not within the predetermined width range, the parameters of the laser etching are adjusted to obtain a new width of the second area until the width of the second area obtained is within the predetermined width range. Such a design can quantify the damage caused by the laser, which is beneficial to optimize the processing technology of the solar cell and improve the efficiency of the solar cell.

Description

Technical Field

[0001] The present application relates to the photovoltaic field, and in particular to a method for processing a solar cell, a solar cell, and a photovoltaic module. Background Art

[0002] With the development of technology, photovoltaic modules have become a common device. The solar cells in photovoltaic modules can convert light energy into electricity. The processing of solar cells usually includes a laser etching step, which can cause damage to the solar cells, resulting in reduced efficiency. Summary of the Invention

[0003] The embodiments of the present application provide a method for processing a solar cell, a solar cell, and a photovoltaic module, which are used to improve the efficiency of the solar cell.

[0004] An embodiment of the present application provides a method for processing a solar cell, the method comprising:

[0005] Laser etching a first area of ​​the substrate, wherein a second area adjacent to the first area is a damaged area;

[0006] Get the width of the second area;

[0007] determining whether the width of the second area is within a predetermined width range;

[0008] When the width of the second region is within a predetermined width range, recording the laser etching parameters as qualified parameters, and processing the battery cell using the qualified parameters;

[0009] When the width of the second region is not within the range of the predetermined width, the laser etching parameters are adjusted and laser etching is performed to obtain a new width of the second region until the width of the second region is within the range of the predetermined width.

[0010] In a possible implementation, the step of laser etching a first area of ​​a substrate, wherein a second area adjacent to the first area is a damaged area, includes:

[0011] performing laser etching on a first area of ​​the substrate;

[0012] removing the oxide layer of the substrate;

[0013] The substrate is wet-etched to form a textured surface in a region adjacent to the first region, and the region where the textured surface is formed is the second region.

[0014] In a possible implementation, before removing the oxide layer of the substrate, the step of laser etching the first region of the substrate, wherein the second region adjacent to the first region is a damaged region, includes:

[0015] The substrate is wet-etched to remove the polysilicon layer, the silicon oxide layer and part of the crystalline silicon layer of the substrate.

[0016] In one possible embodiment, the parameters for laser etching the first area of ​​the substrate are: a laser wavelength of 515 nm to 532 nm, a frequency of 1000 kHz to 1400 kHz, a pulse width of 8 ps to 15 ps, a scanning speed of 3 m / s to 6.5 m / s, and an energy density of 0.1 J / to 1J / ;

[0017] The step of removing the oxide layer of the substrate comprises: wet etching the substrate using a hydrofluoric acid solution with a mass fraction of 30% to 60% for a reaction time of 10 seconds to 30 seconds;

[0018] The step of wet-etching the substrate to remove the polysilicon layer, the silicon oxide layer and a portion of the crystalline silicon layer of the substrate comprises: wet-etching the substrate using a sodium hydroxide solution with a mass fraction of 3% to 8%, a reaction temperature of 60° C. to 85° C., and a reaction time of 100 seconds to 1000 seconds;

[0019] The substrate is wet-etched to form a suede surface in an area adjacent to the first area, where the area where the suede surface is formed is the second area. The step includes: wet-etching the substrate using a sodium hydroxide solution with a mass fraction of 2% to 10% and an alkali polishing additive with a mass fraction of 0.1% to 2%, a reaction temperature of 50°C to 85°C, and a reaction time of 50 seconds to 300 seconds.

[0020] In a possible implementation, wet etching is performed on the substrate to form a textured surface in a region adjacent to the first region, wherein the region where the textured surface is formed is the second region, including:

[0021] The wet etching depth of the substrate does not exceed 10 microns.

[0022] In a possible implementation, before determining whether the width of the second region is within a predetermined width range, the solar cell processing method further includes:

[0023] Processing the solar cell to be tested using the same laser etching parameters, and testing the efficiency of the solar cell to be tested;

[0024] Obtaining the relationship between the energy density of the laser etching, the width of the damaged area, and the efficiency of the solar cell and establishing a model;

[0025] The predicted width of the damaged area is obtained according to the energy density of laser etching through the model, and it is determined whether the predicted width is within the predetermined width range.

[0026] In a possible implementation, the step of adjusting the laser etching parameters includes adjusting at least one parameter of the laser wavelength, frequency, pulse width, power, and energy density.

[0027] The predetermined width does not exceed 3.5 microns.

[0028] A second aspect of the embodiments of the present application provides a solar cell, which is processed by any of the above-mentioned solar cell processing methods.

[0029] A third aspect of the embodiments of the present application provides a photovoltaic assembly, which includes the solar cell described above.

[0030] The embodiments of the present application provide a method for processing a solar cell, a solar cell, and a photovoltaic module. The processing method includes: performing laser etching on a first area of ​​a substrate, and a second area adjacent to the first area is a damaged area. Obtaining the width of the second area. Determining whether the width of the second area is within a predetermined width range. When the width of the second area is within the predetermined width range, the parameters of the laser etching are recorded as qualified parameters, and the qualified parameters are used to process the cell. When the width of the second area is not within the predetermined width range, the parameters of the laser etching are adjusted to obtain a new width of the second area until the width of the second area obtained is within the predetermined width range. The beneficial effect of the embodiments of the present application is to quantify the damage caused by the laser, which is beneficial to optimize the processing technology of the solar cell and improve the efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for processing a solar cell provided in an embodiment of the present application;

[0032] Figure 2 A flowchart of texturing in the second area provided in an embodiment of the present application;

[0033] Figure 3 A flowchart of etching provided in an embodiment of the present application;

[0034] Figure 4 A schematic diagram of a substrate provided in an embodiment of the present application;

[0035] Figure 5 This is a schematic diagram of the substrate provided in an embodiment of the present application after laser etching;

[0036] Figure 6 This is a schematic diagram of the substrate provided in an embodiment of the present application after the first alkaline etching;

[0037] Figure 7 This is a schematic diagram of the substrate provided in an embodiment of the present application after acid etching;

[0038] Figure 8 This is a schematic diagram of the substrate provided in an embodiment of the present application after undergoing a second alkaline etching;

[0039] Figure 9 This is an image of the suede provided in an embodiment of the present application.

[0040] Reference numerals

[0041] 1-base;

[0042] 2-First area;

[0043] 3- Second area;

[0044] 31- Modification area;

[0045] 32-recondensation zone;

[0046] 33-Suede;

[0047] 4-Oxide layer;

[0048] 5-polysilicon layer;

[0049] 6-silicon oxide layer;

[0050] 7-Crystalline silicon layer. DETAILED DESCRIPTION

[0051] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0052] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0053] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0054] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0055] like Figure 1 As shown, an embodiment of the present application provides a method for processing a solar cell, and the method for processing a solar cell includes:

[0056] Step S1, laser etching is performed on the first region 2 of the substrate 1, and the second region 3 adjacent to the first region 2 is a damaged region;

[0057] Step S2, obtaining the width of the second area 3;

[0058] Step S3, determining whether the width of the second area 3 is within a predetermined width range;

[0059] When the width of the second region 3 is within the predetermined width range, the laser etching parameters are recorded as qualified parameters, and the qualified parameters are used to process the solar cell;

[0060] When the width of the second region 3 is not within the predetermined width range, the laser etching parameters are adjusted and laser etching is performed to obtain a new width of the second region 3 until the width of the second region 3 is within the predetermined width range.

[0061] The processing of solar cells such as TOPCon cells, perovskite stacked cells, and back-contact cells usually includes a laser etching step. The purpose of laser etching varies in the processing of different solar cells. Depending on the processing requirements, laser etching can be used for laser film opening, passivation layer removal, surface structure optimization, etc. The area usually etched by laser is the first area 2, i.e., the processing area. The position adjacent to the first area 2 is the second area 3, which is the damaged area. Heat is generated during the laser etching process, and the heat is transferred to the adjacent area of ​​the first area 2, i.e., the heat is transferred to the second area 3 adjacent to the first area 2. The part of the second area 3 close to the first area 2 is the recondensation area 32, and the part away from the first area 2 is the modified area 31. The recondensation area 32 is closer to the first area 2 and receives more heat, resulting in a higher temperature in the recondensation area 32. The substrate 1 in the recondensation area 32 is melted by the heat and then recools and solidifies after the laser etching is completed. The modified area 31 is far away from the first area 2. Compared with the recondensation area 32, the modified area 31 receives relatively less heat. Usually, the portion of the substrate 1 located in the modified area 31 is heated, causing the lattice structure to change, thereby causing the denaturation of this portion of the substrate 1. Compared with other areas of the substrate 1, the properties of the substrate 1 located in the second area 3 change, which will affect the quality of the solar cell during processing, and thus lead to lower efficiency of the solar cell. Usually, the damage caused by laser etching is mainly manifested in the change and modification of the lattice structure, and it is difficult to intuitively obtain the morphology of the damaged area from the appearance. When optimizing the process parameters of solar cells, there is a lack of basis for controlling the damaged area.

[0062] In the solution provided in the embodiment of the present application, the size of the damaged area can be obtained by laser etching the substrate 1 to obtain the second area 3 and obtaining the width of the second area 3. When the width of the second area 3 is larger, the area of ​​the damaged area of ​​the substrate 1 is also larger, and the efficiency of the processed solar cell is also lower. When the width of the second area 3 is greater than the preset width, the second area 3 has a greater impact on the efficiency of the solar cell, and the efficiency of the obtained solar cell is lower. When the width of the second area 3 is within the predetermined width range, the second area 3 has a smaller impact on the efficiency of the solar cell, and the efficiency of the obtained solar cell is higher. Therefore, when the width of the second area 3 is within the predetermined width range, the corresponding laser etching parameters can be recorded as qualified parameters, and when the width of the second area 3 is not within the predetermined width range, the corresponding laser etching parameters can be recorded as unqualified parameters. When the laser etching parameters are qualified parameters, the parameters can be used to process the solar cell. When the laser etching parameters are unqualified, the laser etching parameters are readjusted and steps S1 and S2 are repeated to detect the width of the newly obtained second area 3 and determine whether the width of the new second area 3 is within the predetermined width range until the adjusted laser etching parameters are qualified.

[0063] This method allows the damaged area affected by laser etching to be detected, thereby obtaining the width of the damaged area. Based on the width of the damaged area, the impact of the damaged area on the efficiency of the solar cell can be determined. Therefore, the laser etching parameters can be adjusted and selected to reduce the impact of the damaged area on the efficiency of the solar cell, which is conducive to improving the efficiency of the solar cell. The width of the second area can be used to quantify the size of the damaged area, making it easier for operators to obtain information about the damaged area and more intuitively determine the impact of the damaged area on the solar cell.

[0064] Substrate 1 can be prepared according to the processing flow for solar cells. Along the thickness direction, substrate 1 comprises, in order, an oxide layer 4, a polysilicon layer 5, a silicon oxide layer 6, and a crystalline layer. Depending on the type of substrate 1, substrate 1 can be classified as either n-type or p-type. For n-type substrates, oxide layer 4 is typically a phosphosilicate glass (PSG) layer, and polysilicon layer 5 is n-type polysilicon. For p-type substrates, oxide layer 4 is typically a borosilicate glass (BSG) layer, and polysilicon layer 5 is p-type polysilicon. Crystalline silicon layer 7 of substrate 1 is single crystal silicon.

[0065] In one possible embodiment, before formally processing the solar cell, multiple substrates 1 are selected and processed using different laser etching parameters, and qualified parameters are obtained. The qualified parameters are then used to process the solar cell to improve the overall quality of the solar cell and better meet actual usage requirements.

[0066] like Figure 2 As shown, in a possible implementation, step S1 includes:

[0067] Step S11, performing laser etching on the first region 2 of the substrate 1;

[0068] Step S12, removing the oxide layer 4 of the substrate 1;

[0069] In step S13 , wet etching is performed on the substrate 1 to form a textured surface 33 in a region adjacent to the first region 2 . The region where the textured surface 33 is formed is the second region 3 .

[0070] By laser etching the first region 2 of the substrate 1, damage can be formed in the region adjacent to the first region 2. The oxide layer 4, typically a borosilicate glass layer (BSG) or a phosphorus silicate glass layer (PSG), is removed from the surface to reduce its impact on the texture formation process. After removing the oxide layer 4, the substrate 1 is wet-etched. Because the second region 3 is closer to the first region 2, the substrate 1 in the second region 3 melts and recondenses upon heating, causing the substrate 1 in the recondensation region 32 to denature. The lattice structure of the substrate 1 in the modified region 31 changes upon heating. As a result, the properties of the substrate 1 in the second region 3 differ from those in other locations, resulting in a different wet etching rate. Therefore, during wet etching, the modified region 31 and the recondensation region 32 adjacent to the first region 2 have a slower wet etching rate, and a textured surface 33 can be produced. After the wet etching is completed, the region with the textured surface 33 is the second region 3.

[0071] By measuring the width of the velvet surface 33, the width of the second region 3 can be obtained, and thus the width of the damaged area. The width of the velvet surface 33 can be observed and measured using an optical microscope with a magnification of 20x to 200x. By adopting the solution provided in the embodiments of the present application, the width of the velvet surface 33 can be used as a quantitative indicator of the damaged area, allowing operators to more intuitively obtain information about the damaged area, thereby facilitating the determination of the impact of the damaged area on the cell efficiency.

[0072] In a possible implementation, before step S12, step S1 includes:

[0073] S120 , wet-etching the first region 2 to remove the polysilicon layer 5 , the silicon oxide layer 6 and a portion of the crystalline silicon layer 7 in the first region 2 .

[0074] By wet etching the first region 2, a thickness difference can be formed on the surface of the substrate 1. After texturing, a thickness difference will also exist between the location of the pile surface 33 and the first region 2. This method makes it easier to observe the pile surface 33, reduces the difficulty of measuring the width of the pile surface 33, and helps improve the accuracy of the measurement.

[0075] like Figure 3 As shown, in a possible embodiment, in step S11, the parameters of laser etching are: laser wavelength of 515 nm to 532 nm, frequency of 1000 KHz to 1400 KHz, pulse width of 8 ps to 15 ps, scanning speed of 3 m / s to 6.5 m / s, energy density of 0.1 J / to 1 J / .

[0076] With this design, the substrate 1 can be laser etched to remove the oxide layer 4 and part of the polysilicon layer 5 in the first region 2 , so as to simulate the production process of solar cells and form a damaged area on the substrate 1 .

[0077] Step S12 includes: wet etching the substrate 1 using a hydrofluoric acid solution with a mass fraction of 30% to 60%, with a reaction time of 10 seconds to 30 seconds.

[0078] By acid etching the substrate 1, the oxide layer 4 on the surface of the substrate 1, namely the borosilicate glass layer and the phosphorus silicon glass layer, can be removed. Removing the oxide layer 4 can help improve the quality of the texturing process. At the same time, the presence of the oxide layer 4 can affect the efficiency of the texturing process, resulting in reduced texturing efficiency and increased texturing time, thus affecting efficiency.

[0079] Step S120 includes: wet etching the substrate 1 using a sodium hydroxide solution with a mass fraction of 3% to 8%, with a reaction temperature of 60° C. to 85° C. and a reaction time of 100 seconds to 1000 seconds.

[0080] By performing alkaline etching on the first area 2 of the substrate 1, a thickness difference can be formed between the first area 2 and the second area 3. The velvet surface 33 can be more easily observed after the velvet is made, so that the operator can obtain the width of the velvet surface 33, and then obtain the width of the second area 3, that is, the damaged area, so as to quantify the damage caused by laser etching and obtain damage information more intuitively.

[0081] Step S13 includes: wet etching the substrate 1 using a sodium hydroxide solution with a mass fraction of 2% to 10% and an alkali polishing additive with a mass fraction of 0.1% to 2%, with a reaction temperature of 50° C. to 85° C. and a reaction time of 50 seconds to 300 seconds.

[0082] By performing alkaline etching on the substrate 1, the properties of the substrate 1 located in the second region 3 change, resulting in a different etching rate for the substrate 1 in the second region 3 than for substrate 1 at other locations, and a different surface morphology after etching. Therefore, after alkaline etching, a velvet surface 33 can be obtained in the second region 3. By obtaining the width of the velvet surface 33, the width of the damaged area can be obtained. Since the morphology of the velvet surface 33 is significantly different from that of other locations, the width of the damaged area caused by laser etching can be more intuitively obtained.

[0083] In the solution provided in the embodiment of the present application, after the substrate 1 is laser etched, it is also wet-etched three times, which are alkali etching, acid etching, and alkali etching respectively. Then, a velvet surface 33 can be formed in the damaged area etched by the laser, so that the operator can obtain the width of the damaged area. The impact of the damaged area can be judged based on the width of the damaged area. Usually, the width of the damaged area is negatively correlated with the efficiency of the solar cell, that is, the larger the width of the damaged area, the lower the efficiency of the solar cell, and the smaller the width of the damaged area, the higher the efficiency of the solar cell.

[0084] The structure of substrate 1 is as follows Figure 4 As shown, after laser etching, the structure of the substrate 1 is as follows Figure 5 As shown, the area adjacent to the first area 2 forms a modified area 31 and a recondensation area 32, which corresponds to the second area 3, that is, the damaged area. After the first alkali etching, the structure of the substrate 1 is as follows Figure 6 As shown, the first alkali etching is performed to form a thickness difference between the first region 2 and the second region 3, so that the velvet surface 33 can be measured after the velvet surface 33 is obtained. Figure 7 As shown, the oxide layer 4 on the surface is removed to reduce the influence of the oxide layer 4 on the texturing. After the second alkaline etching, the structure of the substrate 1 is as shown Figure 8 As shown in FIG, due to the denaturation of the substrate 1 in the second region 3, the etching rate at this location is slower than that at other locations, and a velvet surface 33 can be formed. The width of the second region 3 can be obtained by measuring the width of the velvet surface. The obtained velvet surface 33 image is shown in FIG. Figure 9 As shown, Figure 9 The area indicated by the red dotted box is the suede surface 33, which corresponds to the second area 3, that is, the damaged area.

[0085] In a possible implementation, in step S13 , the wet etching depth of the substrate 1 does not exceed 10 micrometers.

[0086] When the wet etching depth exceeds 10 microns, the wet etching depth may be too deep, which in turn increases the etching depth of the second region 3. The damaged area affected by the laser etching may be completely etched, and the textured surface 33 cannot be formed in the second region 3. Therefore, the wet etching depth is usually controlled within 10 microns to form a thickness difference between other areas of the substrate 1 and the second region 3. At the same time, a portion of the damaged area affected by the laser etching can be retained and the textured surface 33 can be formed in the damaged area for easy observation by operators.

[0087] In a possible implementation, before step S3, the processing method may further include:

[0088] S30: Processing the solar cell to be tested using the same laser etching parameters and testing the efficiency of the solar cell to be tested. A correlation between the laser etching energy density, the width of the damaged area, and the efficiency of the solar cell is obtained and a model is established. Using the model, a predicted width of the damaged area is obtained based on the laser etching energy density, and a determination is made as to whether the predicted width is within a predetermined width range.

[0089] Through the solution provided in the embodiments of this application, a model can be established between the laser energy density, the width of the second region 3, and the efficiency of the solar cell. The model can be used to predict the efficiency of the solar cell, thereby determining the impact of the laser-etched damaged area on the efficiency of the solar cell. The model can be used to adjust the laser etching process parameters and reduce the width of the second region 3, thereby optimizing the solar cell production process, improving the efficiency of the solar cell, and reducing production costs.

[0090] The relationship between energy density and the width of the damaged area is: W = 66.67E-12.31, where E is in the range [0.237, 0.267], where W is the width of the damaged area and E is the energy density. The relationship between the width of the damaged area and the efficiency of the solar cell is: eta = -0.0795W + 27.13, where eta is the efficiency of the solar cell and W is the width of the damaged area.

[0091] When processing solar cells, the relationship between energy density and the width of the damaged area, as well as the relationship between the width of the damaged area and the efficiency of the solar cell can be used to calculate and predict the efficiency of the solar cell. By predicting the width of the damaged area and the efficiency of the solar cell by the energy density of the laser, the quality of the processed solar cell and whether the solar cell meets the requirements can be predicted.

[0092] In a possible implementation, the step of adjusting the laser etching parameters includes adjusting at least one parameter of the laser wavelength, frequency, pulse width, power, and energy density.

[0093] Generally, the shorter the laser wavelength, the higher the frequency, the smaller the power, the smaller the pulse width, and the lower the energy density, the less damage the laser etching causes. During adjustment, the overall laser parameters can be adjusted synchronously by adjusting a single parameter.

[0094] Generally, the frequency and power of the laser will affect the energy density and there is a certain correlation. In order to better reduce damage, the power can be reduced while increasing the frequency, which is conducive to reducing the energy density of the laser and thus reducing damage.

[0095] By adjusting the parameters of the laser etching, the damaged area formed by the laser etching on the substrate 1 can be changed, thereby changing the influence of the damaged area on the solar cell.

[0096] In one possible embodiment, the predetermined width of the second region 3 does not exceed 3.5 microns. When the width of the second region 3 is less than 3.5 microns, the damage caused by laser etching has little effect on the efficiency of the solar cell, and the laser etching parameters can be qualified parameters.

[0097] Depending on the type of solar cell and quality requirements, the value of the predetermined width can be adjusted as needed, and the predetermined width can be 0.5 microns, 1.0 microns, 1.5 microns, 2.0 microns, 2.5 microns, 3.0 microns, 3.5 microns, etc.

[0098] As shown in Table 1, the present invention provides experimental data for the experimental group and the control group. The experimental process is as follows:

[0099] Comparative group: An N-type crystalline silicon substrate was prepared and cleaned using standard RCA. A 1.5-nanometer-thick tunneling silicon oxide layer was deposited on the substrate surface using LPCVD. A 200-nanometer-thick amorphous silicon layer was then deposited on the surface of the tunneling silicon oxide layer using LPCVD. High-temperature annealing was performed using LPCVD at 900°C for 60 minutes, while boron atoms were doped into the amorphous silicon, crystallizing the amorphous silicon layer into polycrystalline silicon layer 5. A 50-nanometer-thick BSG layer was also formed on the surface of polycrystalline silicon layer 5, resulting in substrate 1 for the comparative group. Substrate 1 was then sequentially subjected to laser etching, a first alkaline etch, an acid etch, and a second alkaline etch. Laser etching parameters were: wavelength: 532 nm, frequency: 1200 kHz, pulse width: 10 ps, ​​scan speed: 6.5 m / s, and single-pulse energy density: 0.267 J / cm². The first alkaline etch parameters were: 4 wt% NaOH solution, 68°C, and 600 s. The acid etching parameters were: 49wt% HF solution, room temperature, 15 seconds. The second alkaline etching parameters were: 6wt% NaOH solution with an alkaline polishing additive, 78°C, 180 seconds. The width of the velvet surface 33 was measured using an optical microscope and was found to be 5.5 microns. Other parameters of the solar cells in the comparison group are shown in Table 1.

[0100] Experimental Group: An N-type crystalline silicon substrate was prepared and cleaned using standard RCA. A 1.5-nanometer-thick tunneling silicon oxide layer was deposited on the substrate surface using LPCVD. A 200-nanometer-thick amorphous silicon layer was then deposited on the tunneling silicon oxide layer using LPCVD. High-temperature annealing was performed using LPCVD, and boron atoms were doped into the amorphous silicon at 900°C for 60 minutes, crystallizing the amorphous silicon layer into polycrystalline silicon layer 5. A 50-nanometer-thick BSG layer was also formed on the polycrystalline silicon surface, resulting in substrate 1 for the experimental group. Substrate 1 was then sequentially subjected to laser etching, a first alkaline etch, an acid etch, and a second alkaline etch. Laser etching parameters were: wavelength: 532 nm, frequency: 1200 kHz, pulse width: 10 ps, ​​scan speed: 6.5 m / s, and single-pulse energy density: 0.237 J / cm². The first alkaline etch was performed using a 4 wt% NaOH solution at 68°C for 600 s. The acid etching parameters were: 49 wt% HF solution, room temperature, 15 seconds. The second alkaline etching parameters were: 6 wt% NaOH solution with an alkaline polishing additive, 78°C, 180 seconds. Finally, optical microscopy measurement revealed a width of 3.5 microns for the textured surface 33.

[0101]

[0102] Table 1

[0103] The experimental and control groups used the same manufacturing process for substrate 1, the same parameters for the first alkaline etch, the same parameters for the acid etch, and the same parameters for the second alkaline etch. The laser etch energy density differed, but all other parameters remained the same. The laser energy density in the experimental group decreased from 0.267 J / cm² to 0.237 J / cm², and the width of the velvet 33 in the experimental group decreased from 5.5 microns to 3.5 microns. Back-contact solar cells processed using the corresponding laser etching parameters were tested, and the parameters for the solar cell photoelectric conversion efficiency (Eta), open-circuit voltage (Voc), short-circuit current (Isc), and fill factor (FF) are shown in Table 1. As shown in Table 1, the photoelectric conversion efficiency (Eta), open-circuit voltage (Voc), short-circuit current (Isc), and fill factor (FF) of the experimental group were smaller than those of the control group. Furthermore, the photoelectric conversion efficiency, open-circuit voltage, short-circuit current, and fill factor of the experimental group were all improved compared to the control group.

[0104] Combined with the data in Table 1, it can be seen that reducing the width of the velvet surface 33 is beneficial for improving the photovoltaic conversion efficiency and overall performance of the solar cell. Furthermore, according to experimental results, reducing the laser energy density can also reduce the width of the velvet surface 33, which in turn improves the quality of the solar cell. According to the data in Table 1, for every 1 μm reduction in the velvet surface width, the photovoltaic conversion efficiency can be increased by approximately 0.08%.

[0105] According to the data in Table 1, all parameters of the solar cell of the experimental group meet the use requirements. At the same time, since the smaller the width of the suede surface 33, the better the overall performance of the solar cell, when the width of the suede surface 33 is less than 3.5 microns, the overall performance of the solar cell will be better than the performance of the cell of the experimental group in Table 1. Therefore, when the width of the suede surface 33 does not exceed 3.5 microns, it can be considered that the laser-etched damaged area has little effect on the performance of the solar cell, and the obtained solar cell meets the use requirements.

[0106] The present application also provides a solar cell, which can be processed by the solar cell processing method described in any of the above embodiments. The solar cell can be a back contact cell, a perovskite stacked cell, a TOPCon cell, etc.

[0107] An embodiment of the present application further provides a photovoltaic assembly, which includes the solar cell involved in any of the above embodiments.

[0108] The photovoltaic module may also include structures such as a first cover plate, a second cover plate, a first adhesive film, and a second adhesive film. A plurality of solar cells are electrically connected to form a solar cell string, and a plurality of solar cell strings are electrically connected to form a solar cell array. Along the thickness direction of the photovoltaic module, the first adhesive film and the second adhesive film are located on opposite sides of the solar cell array. The first cover plate is located on the side of the first adhesive film away from the solar cell array, and the second cover plate is located on the side of the second adhesive film away from the solar cell array. The first cover plate and the second cover plate are located on the surface of the photovoltaic module and can protect the photovoltaic module. The first adhesive film and the second adhesive film can act as a buffer to reduce the possibility of hidden cracks in the solar cells during lamination and collision, thereby helping to increase the service life of the photovoltaic module.

[0109] Adjacent solar cells can be connected by welding strips. The secondary grid of the solar cell is used to collect the generated photocurrent, and the main grid or connecting wire is used to collect the current of the secondary grid. The welding strip is connected to the main grid or connecting wire to be able to lead out the current.

[0110] In one possible implementation, adjacent solar cells can also be connected using conductive adhesive. Conductive adhesive has excellent conductivity and adhesion. Applying the conductive adhesive to the electrodes of the cell, followed by lamination and curing, forms a conductive path, thereby achieving electrical connection. Connecting with conductive adhesive can reduce the impact of thermal stress and mechanical damage on the solar cells during the connection process, thereby improving the reliability and stability of photovoltaic modules. In actual production, soldering tape and conductive adhesive can be used in combination to save costs and improve reliability.

[0111] The first cover plate and the second cover plate have high structural strength, providing a certain mechanical strength and rigidity for the photovoltaic module to protect the film, solar cells, etc. inside the photovoltaic module, reduce the impact of environmental factors such as rain, wind, sand, and dust on the photovoltaic module, and reduce the possibility of corrosion, wear, and aging of the photovoltaic module, thereby helping to extend the service life of the photovoltaic module.

[0112] When one side of the photovoltaic module is the light-receiving side and the other side is the backlight side, the first cover plate is located on the light-receiving side and the second cover plate is located on the backlight side. The material of the first cover plate is a light-transmitting material, and the material of the second cover plate is a reflective material or a reflective layer is provided. Light can pass through the first cover plate and the first adhesive film to reach the solar cell and be absorbed by the solar cell to generate photocurrent. Light that is not absorbed by the solar cell can be reflected by the second cover plate after passing through the second adhesive film, so that the light can be transmitted back to the solar cell, allowing the solar cell to absorb the light again, thereby improving the solar cell's light absorption efficiency and thus improving the efficiency of the solar cell.

[0113] When both sides of the photovoltaic module are light-receiving sides, the materials of the first cover plate and the second cover plate are both light-transmitting materials. Such a design can help increase the light-receiving area of ​​the photovoltaic module, thereby helping to improve efficiency.

[0114] The cover plate can be made of tempered glass, etc. While having good strength, it also has good light transmittance. When tempered glass is used as the second cover plate, reflective film or reflective coating can be applied to the surface of the tempered glass to achieve light reflection and improve efficiency.

[0115] The first and second adhesive films can be made of EVA, POE, or EPE (EVA-POE-EVA co-extruded film). Positioned between the cover plate and the solar cells, the films act as a bonding and securing mechanism, ensuring the PV module's components remain cohesive and reducing the risk of delamination or shedding during use. The films also act as a seal, preventing moisture, oxygen, and other external substances from entering the module. This reduces corrosion and oxidation of the solar cells and other components, extending the module's service life and reliability.

[0116] The adhesive film can also refract and scatter light to a certain extent, so that the light can be better transmitted and utilized inside the component, which is beneficial to improving the solar cell's absorption efficiency for light, which is beneficial to improving the efficiency of the photovoltaic module and more in line with actual use needs. The solar cell provided in the embodiment of the present application can be a back-contact cell, and the positive and negative electrodes of the back-contact cell are both arranged on the back of the solar cell, that is, the backlight side of the back-contact cell. Such a design can reduce the shading of the grid line to the light-receiving area, which is beneficial to increase the light-receiving area of ​​the solar cell, and thus is beneficial to improving the photoelectric conversion efficiency of the solar cell. At the same time, since the electrodes are concentrated on the same side of the solar cell, when collecting current, the current transmission path is shorter, which is beneficial to reducing the loss during the current transmission process, and can improve the fill factor and conversion efficiency of the cell to be more in line with actual use needs. By arranging the electrode on the backlight side of the solar cell, the possibility of the electrode being corroded or damaged in an outdoor environment can be reduced. By arranging the electrode on the backlight side, the influence of light and ultraviolet rays on the electrode can be reduced, and the rate of electrode aging and performance degradation can be reduced, which is beneficial to extending the service life of the solar cell and improving the reliability of the solar cell. There are usually no electrode grid lines on the front of the back-contact solar cell, which can reduce the possibility of stress concentration problems caused by differences in thermal expansion coefficients, thereby reducing the possibility of cracking and damage to the solar cell during use.

[0117] The embodiments of the present application provide a method for processing a solar cell, a solar cell, and a photovoltaic module. The processing method includes: performing laser etching on a first area 2 of a substrate 1, and a second area 3 adjacent to the first area 2 is a damaged area. Obtaining the width of the second area 3. Determining whether the width of the second area 3 is within a predetermined width range. When the width of the second area 3 is within the predetermined width range, the parameters of the laser etching are recorded as qualified parameters, and the qualified parameters are used to process the cell. When the width of the second area 3 is not within the predetermined width range, the parameters of the laser etching are adjusted to obtain a new width of the second area 3 until the width of the second area 3 obtained is within the predetermined width range. Through such a design, the damage caused by the laser can be quantified, which is beneficial to optimizing the processing technology of the solar cell and improving the efficiency of the solar cell.

Claims

1. A method for processing a solar cell, characterized in that: The processing method comprises: Laser etching is performed on a first area (2) of a substrate (1), wherein a second area (3) adjacent to the first area (2) is a damaged area; Obtaining the width of the second area (3); Determining whether the width of the second area (3) is within a predetermined width range; When the width of the second region (3) is within a predetermined width range, recording the laser etching parameters as qualified parameters, and processing the cell using the qualified parameters; When the width of the second region (3) is not within the range of the predetermined width, adjusting the laser etching parameters and performing laser etching to obtain a new width of the second region (3) until the width of the second region (3) is within the range of the predetermined width; The step of laser etching a first area (2) of a substrate (1), wherein a second area (3) adjacent to the first area (2) is a damaged area, comprises: Laser etching the first area (2) of the substrate (1); removing the oxide layer (4) of the substrate (1); The substrate (1) is wet-etched to form a velvet surface (33) in an area adjacent to the first area (2), and the area where the velvet surface (33) is formed is the second area (3).

2. The method for processing a solar cell according to claim 1, wherein: Before removing the oxide layer (4) of the substrate (1), the step of laser etching the first region (2) of the substrate (1), wherein the second region (3) adjacent to the first region (2) is a damaged region, comprises: The substrate (1) is wet-etched to remove the polysilicon layer (5), the silicon oxide layer (6), and a portion of the crystalline silicon layer (7) of the substrate (1).

3. The method for processing a solar cell according to claim 1, wherein: The parameters for laser etching the first area (2) of the substrate (1) are: laser wavelength of 515 nm to 532 nm, frequency of 1000 KHz to 1400 KHz, pulse width of 8 ps to 15 ps, scanning speed of 3 m / s to 6.5 m / s, energy density of 0.1 J / cm 2 Up to 1J / cm 2 ; The step of removing the oxide layer (4) of the substrate (1) comprises: wet etching the substrate (1) using a hydrofluoric acid solution having a mass fraction of 30% to 60%, with a reaction time of 10 seconds to 30 seconds; The step of wet-etching the substrate (1) to remove the polysilicon layer (5), the silicon oxide layer (6) and a portion of the crystalline silicon layer (7) of the substrate (1) comprises: wet-etching the substrate (1) using a sodium hydroxide solution having a mass fraction of 3% to 8%, a reaction temperature of 60° C. to 85° C., and a reaction time of 100 seconds to 1000 seconds; The substrate (1) is wet-etched to form a velvet surface (33) in an area adjacent to the first area (2), wherein the area where the velvet surface (33) is formed is the second area (3), comprising the steps of wet-etching the substrate (1) using a sodium hydroxide solution having a mass fraction of 2% to 10% and an alkali polishing additive having a mass fraction of 0.1% to 2%, a reaction temperature of 50° C. to 85° C., and a reaction time of 50 seconds to 300 seconds.

4. The method for processing a solar cell according to claim 1, wherein: The substrate (1) is wet-etched to form a velvet surface (33) in an area adjacent to the first area (2), wherein the area where the velvet surface (33) is formed is the second area (3), comprising: The wet etching depth of the substrate (1) does not exceed 10 micrometers.

5. The method for processing a solar cell according to any one of claims 1 to 4, characterized in that: Before determining whether the width of the second region (3) is within a predetermined width range, the solar cell processing method further comprises: Processing the solar cell to be tested using the same laser etching parameters, and testing the efficiency of the solar cell to be tested; Obtaining the relationship between the energy density of the laser etching, the width of the damaged area, and the efficiency of the solar cell and establishing a model; The predicted width of the damaged area is obtained according to the energy density of laser etching through the model, and it is determined whether the predicted width is within the predetermined width range.

6. The method for processing a solar cell according to any one of claims 1 to 4, characterized in that: The step of adjusting the parameters of the laser etching includes adjusting at least one parameter of the laser wavelength, frequency, pulse width, power and energy density.

7. The method for processing a solar cell according to any one of claims 1 to 4, characterized in that: The predetermined width does not exceed 3.5 microns.

8. A solar cell, characterized in that: The solar cell is processed by the solar cell processing method according to any one of claims 1 to 7.

9. A photovoltaic module, characterized in that: The photovoltaic module comprises the solar cell according to claim 8.

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