A method for repairing and evaluating solar cell edge cutting loss

Abstract

The present invention relates to the field of solar cells, and discloses a method for repairing and evaluating the edge cutting loss of solar cells. First, the repair method of the present invention uses ozone water to cool the cut surface of the silicon wafer after laser treatment, which can release oxygen when heated during cooling, thereby forming an oxide layer at the cut surface of the silicon wafer, thereby realizing timely protection of the cut surface of the silicon wafer; the present invention uses a mixed solution of sulfonic acid compounds with hydrogen peroxide as a solvent as an organic / inorganic composite passivation liquid, and the passivation film formed is more tolerant to high temperatures and has better passivation durability than conventional passivation films. Secondly, the evaluation method of the present invention can exclude various environmental and test error factors other than experimental conditions for the same silicon wafer during the test process, and can also reduce the test time and the amount of sample sheets used, and can obtain more accurate test results in a shorter time.

Description

Technical Field

[0001] The invention relates to the field of solar cells, and in particular to a method for repairing and evaluating edge cutting loss of a solar cell. Background Art

[0002] In order to further reduce the internal loss of solar cell modules and increase the output power, the half-cell, multi-cell and shingled module technologies based on laser scribing cut the full-cell solar cell into 1 / 2, 1 / 3 or 1 / n pieces, and then assemble the cut pieces in series and parallel, which can reduce the internal current and line resistance, reduce power loss, and thus increase the module output power and power generation. Therefore, half-cell, shingled and other module technologies have become the mainstream module technologies in the industry.

[0003] The current method of cutting solar cells is mainly non-destructive cutting, the principle of which is: using laser to quickly heat the silicon base material locally, followed by a supporting cooling technology (usually spraying cooling water into the laser processing area) to produce an uneven temperature field, which will produce a temperature gradient on the surface of the material, thereby inducing the generation of thermal stress; the laser spot is in a compressive stress state, while the laser spot is in a tensile stress state before and after. Since the compressive stiffness of brittle materials is much greater than the tensile strength, when the tensile stress reaches the fracture strength of the material, the material will break, and the fracture will steadily expand along the moving track of the laser and subsequent cooling.

[0004] Compared with the traditional lossy cutting method, the above-mentioned non-destructive cutting method reduces the problem of excessive damage to battery performance during laser ablation, but it is inevitable that the edge silicon surface will still be directly exposed to the air after cutting, which will introduce a large number of dangling bonds and defect states, becoming effective carrier recombination centers and reducing battery performance. Taking the current N-type high-efficiency TOPCon solar cell as an example, the absolute value of the battery efficiency drops by 0~0.3% after cutting.

[0005] In order to repair the cutting damage on the edge of solar cells, the ALD method is generally used in the prior art to deposit an aluminum oxide dielectric film on the cut edge of the silicon wafer for passivation, but the investment cost of the ALD equipment required for this method is huge and the cost performance is relatively low. Compared with the ALD method, the passivation method of coating the passivation liquid formed by the organic solution has the advantages of low cost and flexible operation, and has received widespread attention in the market. However, conventional passivation liquids are often composed of pure organic solutions, but they will go through multiple high-temperature processes (such as infrared series welding, lamination, etc.) in the component manufacturing process, which makes the initial organic passivation liquid passivation performance greatly attenuated, and it is impossible to maintain the initial high passivation performance at the end of the final component product. Therefore, how to find new ways to further passivate the cutting damage on the edge of the battery is of great significance to reducing the edge recombination of the battery and improving the CTM value of the component. Summary of the invention

[0006] First, the present invention provides a method for repairing the cutting loss of the edge of a solar cell. The present invention uses ozone water to cool the cut surface of a silicon wafer after laser treatment, which can release oxygen when heated during cooling, thereby forming an oxide layer at the cut surface of the silicon wafer, thereby achieving timely protection of the cut surface of the silicon wafer. The present invention uses a mixed solution of sulfonic acid compounds with hydrogen peroxide as a solvent as an organic / inorganic composite passivation liquid. The passivation film formed is more tolerant to high temperatures and has better passivation durability than conventional organic passivation films.

[0007] Secondly, the present invention provides an evaluation method for the repair effect of edge cutting loss of solar cells. This evaluation method can exclude various environmental and test error factors other than experimental conditions for the same silicon wafer during the test process, and can also reduce the test time and the amount of sample wafers used, and can obtain more accurate test results in a shorter time.

[0008] The specific technical scheme of the present invention is:

[0009] In a first aspect, the present invention provides a method for repairing edge cutting loss of a solar cell, which specifically comprises the following steps:

[0010] S1. Use ozone water as cooling water. Spray ozone water on the laser-cut area of ​​the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0011] The present invention finds that in the gap after laser cutting of silicon wafers and before the cut surface of silicon wafers is coated with a passivation film, on the one hand, since the cut surface of silicon wafers is still briefly exposed to the air, a large number of dangling bonds and defect states are introduced, which become effective recombination centers for carriers and reduce battery performance; on the other hand, the local air composition is complex during the laser cutting process, which will also cause pollution to the cut surface of silicon wafers. For this reason, the present invention cleverly replaces conventional pure water with ozone water to timely cool the cut surface of silicon wafers after laser treatment. Since laser treatment will generate instantaneous high temperature at the cutting point of silicon wafers, when ozone water is sprayed there for cooling, it will release an appropriate amount of oxygen due to heat, thereby timely forming a thinner oxide layer at the cut surface of silicon wafers to protect the cut surface of silicon wafers.

[0012] S2. A mixed solution of sulfonic acid compounds using hydrogen peroxide as a solvent is used as an organic / inorganic composite passivation liquid, which is applied to the cut surface of the silicon wafer and heated and cured in an oxygen-rich environment to form a passivation film.

[0013] In the prior art, in order to repair the cutting damage of the edge of the solar cell, it is reported that an organic solution is applied as a passivation liquid to the cut surface of the silicon wafer to form a passivation film. The disadvantage of this method is that it will go through multiple high-temperature processes (such as infrared series welding, lamination, etc.) during the component manufacturing process, which will cause the passivation performance of the passivation film formed by the organic solution to be greatly attenuated, and it is impossible to maintain the initial high passivation performance at the end of the final component product. For this reason, the present invention uses hydrogen peroxide as a solvent, to which a sulfonic acid compound is added. The passivation liquid prepared is an organic / inorganic composite passivation liquid. After being applied to the cut surface of the silicon wafer, heating can accelerate the cross-linking reaction between the organic molecules in the organic / inorganic composite passivation liquid and promote their bonding with the surface of the substrate. Specifically, during the heating process, the active functional groups in the organic molecules react with the atoms or functional groups on the surface of the substrate to form a covalent bond connection.

[0014] Preferably, in S1, the concentration of ozone in the ozone water is 1-10 mg / L.

[0015] If the concentration of ozone water is too low, the amount of oxygen volatilized during the cell cutting process is not enough to form a denser oxide layer on the silicon wafer on the cutting side, and the air impurity particles will still contaminate the cutting edge during the process. If the concentration of ozone water is too high, it will cause excessive oxygen volatilization during the cutting process. On the one hand, although it will form a denser oxide film on the cutting side, it will also have a greater impact on the grid lines on the surface of the cell, causing the grid lines to be severely oxidized, thereby increasing the line resistance of the grid lines, increasing the series resistance of the entire battery, and affecting the final electrical performance.

[0016] Preferably, in S2, in the organic / inorganic composite passivation solution, the concentration of the hydrogen peroxide is 5-20 wt%, and the concentration of the sulfonic acid compound is 10-50 wt%.

[0017] If the concentration of the sulfonic acid compound is too low, the passivation film formed after the corresponding passivation solution is applied on the cut side of the cell and then heated and cured will be not dense, and the passivation performance will be reduced; if the concentration is too high, on the one hand, the liquid overflow area on the surface of the silicon wafer after coating will be enlarged, which will not only affect the front appearance of the cell, but also cause shading loss; on the other hand, too high a concentration will make the passivation solution after coating take a long time to heat and cure, and it is easy to have undesirable phenomena such as insufficient curing and bubbles inside. If the concentration of the solvent hydrogen peroxide is too low, the oxidation effect of the overall composite passivation solution will be limited, and it will not be able to fully form a dense oxide film on the cut side of the cell; if the concentration is too high, it is difficult for the sulfonic acid compound to fully dissolve in the hydrogen peroxide solution, which will cause the mixed passivation solution to be uneven.

[0018] Preferably, the oxygen content of the oxygen-rich environment in S2 is 30-50 vol%.

[0019] Preferably, in S2, the heating temperature is 100-150° C., and the heating time is 1-10 min.

[0020] In a second aspect, the present invention provides a method for evaluating the repair effect of solar cell edge cutting loss, which specifically comprises the following steps:

[0021] 1) Use ozone water as cooling water. Spray ozone water on the laser-cut area of ​​the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0022] 2) Select the cut silicon wafers as samples and perform the first electrical properties and / or PL test on them.

[0023] 3) Divide the cut side of the silicon wafer into at least one blank control area (non-passivation) and at least one passivation test area.

[0024] 4) Apply different passivation solutions to the surface of the corresponding passivation test area to form a passivation film.

[0025] 5) Conduct a second electrical performance and / or PL test on solar cells in different areas and compare the results with the first test results.

[0026] In the prior art, for the conventional edge passivation battery evaluation method, the general steps are: (1) first perform the corresponding electrical performance or PL test after conventional silicon wafer cutting; (2) apply the passivation solution; (3) perform the electrical performance or PL test again. Since the intermediate process between silicon wafer cutting and passivation solution coating will inevitably be exposed to the air for a period of time, the cut side will inevitably be affected by the natural oxide layer, which will cause the test results to be different from the actual situation, thereby increasing the risk of misjudgment. To this end, the present invention provides the above-mentioned evaluation method. According to the method of the present invention, various environmental and test error factors other than experimental conditions for the same silicon wafer can be excluded during the test process, and the test time and sample usage can also be reduced, so that more accurate test results can be obtained in a shorter time.

[0027] Preferably, in 1), the concentration of ozone in the ozone water is 1-10 mg / L.

[0028] Preferably, in 3), the size of each region is the same.

[0029] Preferably, in 4), one of the passivation solutions is an organic / inorganic composite passivation solution, which is a mixed solution of sulfonic acid compounds with hydrogen peroxide as solvent; wherein the concentration of hydrogen peroxide is 5-20 wt%, and the concentration of the sulfonic acid compound is 10-50 wt%.

[0030] Preferably, in 4), the passivation film is formed by heating and curing in an oxygen-rich environment.

[0031] More preferably, the oxygen content of the oxygen-rich environment is 30-50 vol%.

[0032] More preferably, the temperature of the heating curing is 100-150° C. and the time is 1-10 min.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] (1) The present invention ingeniously uses ozone water instead of conventional pure water to cool the cut surface of the silicon wafer after laser treatment. Ozone water can release an appropriate amount of oxygen when heated while cooling, thereby forming a thinner oxide layer on the cut surface of the silicon wafer in time, thereby achieving timely protection of the cut surface of the silicon wafer.

[0035] (2) The present invention uses a hydrogen peroxide solution containing poly (4-styrene sulfonic acid) as an organic / inorganic composite passivation solution, which can be coated on the cut surface of a silicon wafer and then heated in an oxygen-rich environment to form a passivation film. Compared with conventional passivation films, the passivation film has a stronger tolerance to high temperatures and better passivation durability.

[0036] (3) The present invention provides a method for evaluating the repair effect of edge cutting loss of solar cells. According to the evaluation method of the present invention, various environmental and test error factors other than experimental conditions for the same silicon wafer can be eliminated during the test process, and the test time and sample usage can also be reduced, so that more accurate test results can be obtained in a shorter time. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The PL test results of the finished whole cell before cutting (a) and the PL test results of the cell after cutting in half (b).

[0038] Figure 2 These are appearance photos of the side of the cell after cutting in Example 1 of the present invention, before coating (a) and after coating with an organic / inorganic composite passivation solution (b).

[0039] Figure 3 The PL test results (a) of the cell after cutting in Example 1 of the present invention, the PL test results (b) after coating with organic / inorganic composite passivation solution, and the PL test results (c) after simulating high temperature of infrared series welding.

[0040] Figure 4 This is a photo of the appearance of a small component after lamination of battery cells processed by Example 1 of the present invention.

[0041] Figure 5 The PL test results (a) of the cell after cutting, (b) of the cell after coating with organic / inorganic composite passivation solution, and (c) of the small component after lamination in Example 1 of the present invention are shown.

[0042] Figure 6 The PL test results of the cell after cutting (a) in Comparative Example 1, the PL test results after coating with conventional organic passivation solution (b) and the PL test results after simulating high temperature of infrared series welding (c) are shown.

[0043] Figure 7 The PL test results of the cell after cutting (a) in Comparative Example 1, the PL test results after coating with conventional organic passivation solution (b) and the PL test results of the small component after lamination (c) are shown.

[0044] Figure 8 The PL test results of the cell after cutting in Comparative Example 2 (a), the PL test results after coating with conventional organic passivation solution (b), and the PL test results after simulating high temperature of infrared series welding (c).

[0045] Fig. 9 The PL test results of the cell after cutting in Comparative Example 2 (a), the PL test results after coating with conventional organic passivation solution (b), and the PL test results of the small component after lamination (c).

[0046] Fig.10 Schematic diagram of the process of the evaluation method of Example 2 of the present invention.

[0047] Fig.11 This is a graph showing the PL test results after the cut side of the cell is coated with an organic / inorganic passivation solution in Example 2 of the present invention.

[0048] Fig.12 This is a graph showing the battery PL test results of the blank control area and the two passivation test areas after coating with the passivation solution in Example 3 of the present invention.

[0049] Fig.13 This is a graph showing the battery PL test results of the blank control area and the two passivation test areas after coating with the passivation solution in Example 4 of the present invention. DETAILED DESCRIPTION

[0050] The present invention will be further described below in conjunction with the embodiments.

[0051] Overall embodiment

[0052] First, a method for repairing the cutting loss of a solar cell edge comprises the following steps:

[0053] S1. Use ozone water as cooling water. Spray ozone water on the laser-cut area of ​​the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0054] The present invention finds that in the gap after laser cutting of silicon wafers and before the cut surface of silicon wafers is coated with a passivation film, on the one hand, since the cut surface of silicon wafers is still briefly exposed to the air, a large number of dangling bonds and defect states are introduced, which become effective recombination centers for carriers and reduce battery performance; on the other hand, the local air composition is complex during the laser cutting process, which will also cause pollution to the cut surface of silicon wafers. For this reason, the present invention cleverly replaces conventional pure water with ozone water to timely cool the cut surface of silicon wafers after laser treatment. Since laser treatment will generate instantaneous high temperature at the cutting point of silicon wafers, when ozone water is sprayed there for cooling, it will release an appropriate amount of oxygen due to heat, thereby timely forming a thinner oxide layer at the cut surface of silicon wafers to protect the cut surface of silicon wafers.

[0055] In some preferred implementation cases, in S1, the concentration of ozone in the ozone water is 1-10 mg / L. If the concentration of ozone water is too low, the amount of oxygen volatilized during the cell cutting process is insufficient to form a denser oxide layer on the silicon wafer on the cutting side, and air impurity particles will still contaminate the cutting edge during the process. If the concentration of ozone water is too high, it will cause excessive oxygen volatilization during the cutting process. On the one hand, although it will form a denser oxide film on the cutting side, it will also have a greater impact on the grid lines on the surface of the cell, causing the grid lines to be severely oxidized, thereby increasing the line resistance of the grid lines, increasing the series resistance of the entire battery, and affecting the final electrical performance.

[0056] S2. A mixed solution of sulfonic acid compounds using hydrogen peroxide as a solvent is used as an organic / inorganic composite passivation solution, which is applied to the cut surface of the silicon wafer and heated in an oxygen-rich environment to react to form a passivation film.

[0057] In the prior art, in order to repair the cutting damage of the edge of the solar cell, it is reported that an organic solution is applied as a passivation liquid to the cut surface of the silicon wafer to form a passivation film. The disadvantage of this method is that it will go through multiple high-temperature processes (such as infrared series welding, lamination, etc.) during the component manufacturing process, which will cause the passivation performance of the passivation film formed by the organic solution to be greatly attenuated, and it is impossible to maintain the initial high passivation performance at the end of the final component product. For this reason, the present invention uses hydrogen peroxide as a solvent, to which a sulfonic acid compound is added. The passivation solution prepared is an organic / inorganic composite passivation solution. The passivation film formed after being applied to the cut surface of the silicon wafer has a stronger tolerance to high temperatures and better passivation durability than conventional passivation films.

[0058] In some preferred implementation cases, in S2, in the organic / inorganic composite passivation solution, the concentration of hydrogen peroxide is 5~20 wt%, and the concentration of sulfonic acid compound is 10~50 wt%. If the concentration of sulfonic acid compound is too low, the passivation film formed by heating and curing after the corresponding passivation solution is applied on the cut side of the battery cell is not dense, and the passivation performance is reduced; if the concentration is too high, on the one hand, the liquid overflow area on the surface of the silicon wafer after coating will be enlarged, which will not only affect the front appearance of the battery cell, but also cause shading loss; on the other hand, too high a concentration will make the passivation solution after coating take a long time in the heating and curing process, and it is easy to have insufficient curing, bubbles inside and other undesirable phenomena. If the concentration of solvent hydrogen peroxide is low, the oxidation effect of the overall composite passivation solution will be limited, and it will not be possible to fully form a dense oxide film on the cut side of the battery; if the concentration is high, it is difficult for the sulfonic acid compound to fully dissolve in the hydrogen peroxide solution, which will cause the mixed passivation solution to be uneven.

[0059] In some preferred implementation cases, the oxygen content of the oxygen-rich environment in S2 is 30-50 vol%.

[0060] In some preferred implementation cases, in S2, the heating temperature is 100-150° C., and the heating time is 1-10 min.

[0061] Secondly, a method for evaluating the repair effect of solar cell edge cutting loss, which specifically includes the following steps:

[0062] 1) Use ozone water as cooling water. Spray ozone water on the laser-cut area of ​​the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0063] In some preferred implementation cases, in 1), the concentration of ozone in the ozone water is 1-10 mg / L.

[0064] 2) Select the cut silicon wafers as samples and perform the first electrical properties and / or PL test on them.

[0065] 3) Divide the cut side of the silicon wafer into at least one blank control area (non-passivation) and at least one passivation test area.

[0066] In some preferred implementation cases, in 3), the size of each region is the same.

[0067] 4) Apply different passivation solutions to the surface of the corresponding passivation test area to form a passivation film.

[0068] 5) Conduct a second electrical performance and / or PL test on solar cells in different areas and compare the results with the first test results.

[0069] In the prior art, for the conventional edge passivation battery evaluation method, the general steps are: (1) first perform the corresponding electrical performance or PL test after conventional silicon wafer cutting; (2) apply the passivation solution; (3) perform the electrical performance or PL test again. Since the intermediate process between silicon wafer cutting and passivation solution coating will inevitably be exposed to the air for a period of time, the cut side will inevitably be affected by the natural oxide layer, which will cause the test results to be different from the actual situation, thereby increasing the risk of misjudgment. To this end, the present invention provides the above-mentioned evaluation method. According to the method of the present invention, various environmental and test error factors other than experimental conditions for the same silicon wafer can be excluded during the test process, and the test time and sample usage can also be reduced, so that more accurate test results can be obtained in a shorter time.

[0070] In some preferred implementation cases, in 4), one of the passivation solutions is an organic / inorganic composite passivation solution, which is a mixed solution of sulfonic acid compounds with hydrogen peroxide as a solvent; wherein the concentration of the hydrogen peroxide solution is 5~20 wt%; and the concentration of the sulfonic acid compound is 10~50 wt%.

[0071] In some preferred implementation cases, in 4), the passivation film is formed by heating and curing in an oxygen-rich environment.

[0072] In some more preferred implementation cases, in 4), the oxygen content of the oxygen-rich environment is 30-50 vol%.

[0073] In some more preferred implementation cases, in 4), the temperature of the heating curing is 100-150° C., and the time is 1-10 min.

[0074] Specific Examples and Comparative Examples

[0075] (A) Repair method for cutting loss on the edge of solar cells.

[0076] Example 1

[0077] A method for repairing solar cell edge cutting loss, which specifically comprises the following steps:

[0078] S1. Use ozone water with an ozone concentration of about 4 mg / L as cooling water. Spray ozone water on the laser-cut area of ​​the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0079] S2. A hydrogen peroxide solution containing poly (4-styrene sulfonic acid) is used as an organic / inorganic composite passivation solution. In the organic / inorganic composite passivation solution, the concentration of the hydrogen peroxide solution is about 10 wt%, and the concentration of poly (4-styrene sulfonic acid) is about 15 wt%. The organic / inorganic composite passivation solution is applied to the cut surface of the silicon wafer, and heated at 140°C for 3 min in an oxygen-rich environment with an oxygen content of about 35 vol% to form a passivation film.

[0080] like Figure 1 The figure shows the PL test results of the finished whole cell before cutting in the conventional cutting method ( Figure 1 (a)) and the test results of the PL of the battery cell after cutting in half ( Figure 1 The results show Figure 1 In (b), the edge of the battery silicon wafer turns red after cutting, indicating that if no passivation protection measures are taken, the performance of the battery silicon wafer edge will change significantly after cutting.

[0081] Figure 2 The side of the cell after cutting in Example 1 of the present invention is not coated with passivation solution ( Figure 2 (a)) and after coating with organic / inorganic composite passivation solution ( Figure 2 (b) Appearance photo. Figure 3 PL test result diagram of the cell after cutting in Example 1 of the present invention ( Figure 3 (a)), PL test results after coating with organic / inorganic composite passivation solution ( Figure 3 (b)) and the PL test results after simulating high temperature of infrared series soldering ( Figure 3 (c)). The results show that the passivation film formed by coating the organic / inorganic composite passivation solution of Example 1 of the present invention on the cut side of the battery can effectively passivate the cut edge, and the passivation performance does not show a significant decrease after the subsequent simulated infrared serial welding process (the color of the cut position of the battery cell does not obviously turn red after infrared serial welding).

[0082] Figure 4 This is a photograph of the appearance of a small module obtained by laminating the battery cells processed by Example 1 of the present invention.

[0083] Figure 5 PL test result diagram of the cell after cutting in Example 1 of the present invention ( Figure 5 (a)), PL test results after coating with organic / inorganic composite passivation solution ( Figure 5 (b)) and the PL test results of the small component after lamination ( Figure 5(c)). The results show that the passivation film formed by coating the organic / inorganic composite passivation solution of Example 1 of the present invention on the cut side of the battery can not only effectively passivate the cut edge, but also the passivation performance does not show a significant decrease in the subsequent component end lamination process (the color of the battery cell cut position does not obviously turn red after lamination).

[0084] Comparative Example 1 (Compared with Example 1, the only difference is that conventional organic passivation solution is used in S2)

[0085] A method for repairing solar cell edge cutting loss, which specifically comprises the following steps:

[0086] S1. Use ozone water with an ozone concentration of about 4 mg / L as cooling water. Spray ozone water on the laser-cut area of ​​the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0087] S2. An ethanol solution containing (2-(9H-carbazole-9-yl)ethyl)phosphonic acid is used as a conventional organic passivation solution. The concentration of (2-(9H-carbazole-9-yl)ethyl)phosphonic acid in the conventional organic passivation solution is about 10 wt %. The conventional organic passivation solution is then applied to the cut surface of the silicon wafer, and heated at 100° C. in an air environment for 3 min to form a passivation film.

[0088] Figure 6 The PL test result after the cell was cut in Comparative Example 1 ( Figure 6 (a)), PL test results after coating with conventional organic passivation solution ( Figure 6 (b)) and PL test results after simulating infrared series soldering at high temperature ( Figure 6 (c)). The results show that although the conventional organic passivation liquid of Comparative Example 1 can effectively passivate the cut edge of the cell after being coated on the cut side of the cell to form a passivation film, its passivation performance will be significantly reduced after the subsequent simulated infrared series welding process (the color of the cell cut position will obviously turn red after infrared series welding).

[0089] Figure 7 The PL test result after the cell was cut in Comparative Example 1 ( Figure 7 (a)), PL test results after coating with conventional organic passivation solution ( Figure 7 (b)) and the PL test results of the small component after lamination ( Figure 7 (c)). The results show that the passivation film formed by coating the conventional organic passivation liquid of Comparative Example 1 on the cut side of the battery can also effectively passivate the cut edge, but the passivation performance will be significantly reduced after the subsequent component end lamination process (the color of the battery cell cut position will obviously turn red after lamination).

[0090] Comparative Example 2 (Compared with Example 1, the only difference is that conventional organic passivation solution is used in S2)

[0091] A method for repairing solar cell edge cutting loss, which specifically comprises the following steps:

[0092] S1. Use ozone water with an ozone concentration of about 4 mg / L as cooling water. Spray ozone water on the laser-cut area of ​​the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0093] S2. An ethanol solution containing perfluorosulfonic acid resin is used as a conventional organic passivation liquid. The concentration of perfluorosulfonic acid resin in the conventional organic passivation liquid is about 12 wt %. The conventional organic passivation liquid is then applied to the cut surface of the silicon wafer and heated at 110° C. in an air environment for 3 min to form a passivation film.

[0094] Figure 8 The PL test result after the cell was cut in Comparative Example 2 ( Figure 8 (a)), PL test results after coating with conventional organic passivation solution ( Figure 8 (b)) and PL test results after simulating infrared series soldering at high temperature ( Figure 8 (c)). The results show that although the conventional organic passivation liquid of Comparative Example 2 can effectively passivate the cut edge of the cell after being coated on the cut side of the cell to form a passivation film, its passivation performance will be significantly reduced after the subsequent simulated infrared series welding process (the color of the cell cut position will obviously turn red after infrared series welding).

[0095] Fig. 9 The PL test result after the cell was cut in Comparative Example 2 ( Fig. 9 (a)), PL test results after coating with conventional organic passivation solution ( Fig. 9 (b)) and the PL test results of the small component after lamination ( Figure 7 (c)). The results show that the passivation film formed by coating the conventional organic passivation liquid on the cut side of the battery in Comparative Example 2 can also effectively passivate the cut edge, but the passivation performance will be significantly reduced after the subsequent component end lamination process (the color of the battery cell cut position will obviously turn red after lamination).

[0096] (ii) Evaluation of the repair effect of different passivation solutions on edge cutting loss of solar cells.

[0097] Example 2

[0098] A method for evaluating the repair effect of solar cell edge cutting loss, which specifically includes the following steps:

[0099] 1) Using ozone water with an ozone concentration of 4 mg / L as cooling water, the laser-cut area on the silicon wafer is sprayed with ozone water immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0100] 2) Select the cut silicon wafer as a sample and perform the first PL test on it.

[0101] 3) Divide the cut side of the silicon wafer into a blank control area (non-passivation) and a passivation test area.

[0102] 4) The blank control area was not coated with the passivation solution, and the organic / inorganic composite passivation solution in Example 1 was coated on the surface of the passivation test area, and heated at 140° C. for 3 min in an oxygen-rich environment with an oxygen content of about 35 vol% to form a passivation film.

[0103] 5) Perform a second PL test on the blank control area and passivation test area of ​​the solar cell and compare the results with the first test.

[0104] Fig.10 Schematic diagram of the evaluation method in Example 2 of the present invention. In this embodiment, since the blank control group and the passivation test group are both performed on the same cell cutting edge, any error influence other than the experimental conditions can be excluded in the corresponding experimental process, and the performance of the coated composite passivation solution and the uncoated passivation solution can be clearly compared.

[0105] Fig.11 This is a PL test result diagram of the cut side of the cell after coating the organic / inorganic passivation solution in Example 2 of the present invention. Fig.11 It can be seen that the edge of the battery after coating with the organic / inorganic passivation solution becomes significantly brighter, while the uncoated area (blank control area) is still red. This test result directly proves that the passivation film formed by the organic / inorganic passivation solution of Example 1 has an obvious passivation effect.

[0106] Example 3 (Compared with Example 2, the difference is that the number of passivation test areas is 2, one of which is coated with the conventional organic passivation solution in Comparative Example 1, and the other is coated with the organic / inorganic composite passivation solution in Example 1)

[0107] A method for evaluating the repair effect of solar cell edge cutting loss, which specifically includes the following steps:

[0108] 1) Using ozone water with an ozone concentration of 4 mg / L as cooling water, the laser-cut area on the silicon wafer is sprayed with ozone water immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0109] 2) Select the cut silicon wafer as a sample and perform the first PL test on it.

[0110] 3) Divide the cut side of the silicon wafer into a blank control area (non-passivation) and two passivation test areas.

[0111] 4) The blank control area was not coated with the passivation solution, the organic / inorganic composite passivation solution in Example 1 was coated on the surface of one of the passivation test areas, and the conventional organic passivation solution in Comparative Example 1 was coated on the surface of the other passivation test area, and the reaction was heated at 140°C for 3 min in an oxygen-rich environment with an oxygen content of about 35 vol%, and passivation films were formed on the above two passivation test areas.

[0112] 5) Perform a second PL test on the blank control area and two passivation test areas of the solar cell and compare the results with the first test.

[0113] Fig.12 The figure is a battery PL test result diagram of the blank control area and the two passivation test areas after coating the passivation solution in Example 3 of the present invention. In Example 3, the cut side of the battery cell is divided into three equal areas, of which the middle area is the blank control area, the upper area is the area after coating the conventional organic passivation solution of Comparative Example 1, and the lower area is the area after coating the organic / inorganic composite passivation solution of Example 1 of the present invention. After the PL test, it can be clearly observed that the cut area coated with the passivation solution becomes significantly brighter, while the blank control area is still red, and the brightness of the area coated with the organic / inorganic composite passivation solution of Example 1 is slightly higher than that of the area coated with the conventional organic passivation solution of Comparative Example 1. This test result shows that the organic / inorganic composite passivation solution of Example 1 has a better passivation effect than the conventional organic passivation solution of Comparative Example 1.

[0114] Example 4 (Compared with Example 2, the difference is that the number of passivation test areas is 2, one of which is coated with the conventional organic passivation solution in Comparative Example 2, and the other is coated with the organic / inorganic composite passivation solution in Example 1)

[0115] A method for evaluating the repair effect of solar cell edge cutting loss, which specifically includes the following steps:

[0116] 1) Using ozone water with an ozone concentration of 4 mg / L as cooling water, the laser-cut area on the silicon wafer is sprayed with ozone water immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time.

[0117] 2) Select the cut silicon wafer as a sample and perform the first PL test on it.

[0118] 3) Divide the cut side of the silicon wafer into a blank control area (non-passivation) and two passivation test areas.

[0119] 4) The blank control area was not coated with the passivation solution, the organic / inorganic composite passivation solution in Example 1 was coated on the surface of one of the passivation test areas, and the conventional organic passivation solution in Comparative Example 2 was coated on the surface of the other passivation test area, and the reaction was heated at 140°C for 3 min in an oxygen-rich environment with an oxygen content of about 35 vol%, and passivation films were formed on the two passivation test areas respectively.

[0120] 5) Perform a second PL test on the blank control area and two passivation test areas of the solar cell and compare the results with the first test.

[0121] Fig.13 The figure is a battery PL test result diagram of the blank control area and the two passivation test areas after coating the passivation solution in Example 3 of the present invention. In Example 3, the cut side of the battery cell is divided into three equal areas, of which the middle area is the blank control area, the upper area is the area after coating the conventional organic passivation solution of Comparative Example 2, and the lower area is the area after coating the organic / inorganic composite passivation solution of Example 1 of the present invention. After the PL test, it can be clearly observed that the cut area coated with the passivation solution becomes significantly brighter, while the blank control area is still red, and the brightness of the area coated with the organic / inorganic composite passivation solution of Example 1 is slightly higher than that of the conventional organic passivation solution coated area of ​​Comparative Example 2. This test result shows that the organic / inorganic composite passivation solution of Example 1 has a better passivation effect than the conventional organic passivation solution of Comparative Example 2. In summary, the testing method of the present invention can not only accurately compare the result differences between the control group and each experimental group, but also reduce the number of experimental sheets and reduce costs.

[0122] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0123] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for repairing the cutting loss of a solar cell edge, characterized in that include: S1. Use ozone water as cooling water, spray ozone water on the laser-cut area on the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer is formed on the cut surface of the silicon wafer in time; S2. A mixed solution of a sulfonic acid compound using hydrogen peroxide as a solvent is used as an organic / inorganic composite passivation liquid, which is applied to the cut surface of a silicon wafer and heated and cured in an oxygen-rich environment to form a passivation film; the sulfonic acid compound is poly-4-styrene sulfonic acid.

2. The repair method according to claim 1, characterized in that: In S1, the concentration of ozone in the ozone water is 1-10 mg / L.

3. The repair method according to claim 1, characterized in that: In S2, in the organic / inorganic composite passivation solution, the concentration of hydrogen peroxide is 5-20 wt%, and the concentration of the sulfonic acid compound is 10-50 wt%.

4. The repair method according to claim 1, characterized in that: The oxygen content of the oxygen-rich environment in S2 is 30-50 vol%.

5. The repair method according to claim 1 or 4, characterized in that: In S2, the heating temperature is 100-150°C and the heating time is 1-10 min.

6. A method for evaluating the repair effect of solar cell edge cutting loss, characterized in that include: 1) Use ozone water as cooling water, spray ozone water on the laser-cut area of ​​the silicon wafer immediately after laser treatment to cool it and create a local oxygen-rich environment, so that an oxide layer can be formed on the cut surface of the silicon wafer in time; 2) Conduct the first electrical performance and / or PL test on the cut silicon wafers; 3) dividing the cut side of the silicon wafer into at least one blank control area and at least one passivation test area; 4) applying different passivation solutions to the surface of the corresponding passivation test area to form a passivation film; one of the passivation solutions is an organic / inorganic composite passivation solution, which is a mixed solution of sulfonic acid compounds with hydrogen peroxide as a solvent; the sulfonic acid compound is poly-4-styrene sulfonic acid; 5) Conduct a second electrical performance and / or PL test on solar cells in different areas and compare the results with the first test results.

7. The evaluation method according to claim 6, characterized in that: 1), the concentration of ozone in the ozone water is 1-10 mg / L.

8. The evaluation method according to claim 6, characterized in that: 3), each region has the same size.

9. The evaluation method according to claim 6, characterized in that: 4), the concentration of hydrogen peroxide in the organic / inorganic composite passivation solution is 5-20 wt%, and the concentration of the sulfonic acid compound is 10-50 wt%.

10. The evaluation method according to claim 9, characterized in that: 4) In the process, the passivation film is formed by heating and curing in an oxygen-rich environment.

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