TOPCon solar cell, preparation method thereof and TOPCon solar cell

Abstract

The invention provides a preparation method of a TOPCon solar cell. The preparation method comprises the following steps: carrying out oxidation modification on a cut cell; the cutting edge of the battery piece is coated with passivation liquid, a passivation film is formed, the passivation liquid comprises at least one passivation agent, and the passivation agent passivates the cutting edge through the oxidation effect. The invention further provides the TOPCon solar cell piece prepared according to the preparation method, and the TOPCon solar cell comprising the TOPCon solar cell piece. According to the preparation method of the TOPCon solar cell, the cut edge of the cell is modified through oxidation, and then the cut edge of the cell is coated with the passivation solution, so that the passivation solution is more uniformly distributed on the cut edge of the cell, the adhesive force of the passivation solution on the cut surface is improved, the passivation effect is improved, and the service life of the cell is prolonged. And the passive film can be subjected to subsequent infrared and lamination processes, so that the damage is reduced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of solar cells, and in particular to a method for preparing a TOPCon solar cell sheet, a TOPCon solar cell sheet, and a TOPCon solar cell. Background Art

[0002] With the application of half-cut technology in solar cells, solar cells are cut into half slices from full slices to reduce the internal current and line resistance of the cell. The current dicing technology will cause very serious damage to the cell, resulting in a large number of defect states and dangling bonds on the cutting edge of the cell, which will lead to serious recombination of the cell and serious loss of efficiency of the battery module. In order to maintain a good conversion efficiency of the cell after cutting, the research on cell edge passivation technology has become an indispensable topic. Summary of the invention

[0003] In order to solve the above technical problems, the present disclosure provides a method for preparing a TOPCon solar cell, comprising:

[0004] Perform oxidation modification on the cut battery cells;

[0005] A passivation solution is coated on the cut edge of the battery cell to form a passivation film, wherein the passivation solution includes at least one passivating agent, and the passivating agent passivates the cut edge through oxidation.

[0006] In some embodiments, the passivating agent carries a sulfonic acid functional group, a phosphoric acid functional group, or a carboxylic acid functional group.

[0007] In some embodiments, the passivating agent includes one or more of dodecylbenzenesulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and poly(4-styrenesulfonic acid).

[0008] In some embodiments, the passivating agent includes one or more of dodecylbenzenesulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and poly(4-styrenesulfonic acid).

[0009] In some embodiments, the passivation solution further includes an organic solvent, and the organic solvent is selected from one or more of isopropanol, ethylene glycol, ethanol, and deionized water.

[0010] In some embodiments, the organic solvent includes deionized water, and the passivating agent includes poly(4-styrene sulfonic acid); the passivating solution and the deionized water are mixed in a volume ratio of 1:1 to obtain the passivating solution.

[0011] In some embodiments, the step of performing oxidation modification on the cut battery cells includes:

[0012] The battery cell is oxidized at high temperature using hydrogen peroxide in a high temperature environment.

[0013] In some embodiments, in the step of oxidatively modifying the battery cell using hydrogen peroxide in a high temperature environment, the high temperature oxidation temperature is 120-160° C., and the high temperature oxidation time is 5-30 min.

[0014] In some embodiments, after the step of coating the passivation solution on the cut edge of the cell, the preparation method further comprises:

[0015] In a preset temperature and humidity environment, the battery cell is placed vertically for a preset time, wherein the cut edge faces downward.

[0016] The disclosed embodiment also provides a TOPCon solar cell obtained according to the above-mentioned method for preparing the TOPCon solar cell.

[0017] The present disclosure also provides a TOPCon solar cell, which includes a TOPCon solar cell obtained according to the preparation method of the TOPCon solar cell.

[0018] The preparation method of TOPCon solar cell disclosed in the present invention first oxidizes and modifies the cut edge of the cell, and then coats the cut edge with a passivation liquid. The passivator in the passivation liquid passivates the cut edge by oxidation, which not only makes the passivation liquid more evenly distributed on the cut edge of the cell, but also improves the adhesion between the passivation liquid and the cut edge, thereby improving the passivation effect. In addition, the passivation film can remain stable in the subsequent infrared and lamination processes of the component production line, thereby ensuring the passivation effect on the cut edge of the cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the TOPCon solar cell cutting damage passivation method according to the present disclosure.

[0020] Figure 2 It is a device used for keeping the coated battery sheet still in the method disclosed in the present invention.

[0021] Figure 3 The PL brightness of the cut edge of the unpassivated half-cell before and after infrared and lamination.

[0022] Figure 4 The PL brightness of the cut edge of the passivated half-cell before and after infrared and lamination. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the technical solution of the present disclosure is described in detail below with reference to the accompanying drawings.

[0024] Example embodiments will be described more fully below with reference to the accompanying drawings, but the example embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, the purpose of providing these embodiments is to make the present disclosure thorough and complete and to enable those skilled in the art to fully understand the scope of the present disclosure.

[0025] In the absence of conflict, the various embodiments of the present disclosure and the various features therein may be combined with each other.

[0026] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0027] The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will also be understood that when the terms "comprising" and / or "made of" are used in this specification, the presence of the features, wholes, steps, operations, elements and / or components is specified, but the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof is not excluded.

[0028] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted as having an idealized or overly formal meaning unless explicitly defined as such herein.

[0029] The present disclosure provides a method for preparing a TOPCon solar cell. Figure 1 As shown, including:

[0030] S1, oxidatively modifying the cut battery cells;

[0031] S2. Coating a passivation solution on the cut edge of the battery cell to form a passivation film, wherein the passivation solution includes at least one passivating agent, and the passivating agent passivates the cut edge by oxidation.

[0032] The embodiment of the present disclosure provides a passivation liquid, which is prepared from at least one passivating agent, and the passivating agent passivates the cut edge by oxidation. Before applying the passivation liquid, the cut battery cell is oxidatively modified so that the cut edge of the battery cell changes from hydrophobic to hydrophilic, and the lattice defects of the cut edge are repaired, so that after the passivation liquid is applied to the cut edge, the passivation liquid can be more evenly distributed on the cut edge, and the adhesion between the passivation liquid and the cut edge can be improved.

[0033] For component production, after half a cell is loaded, it needs to pass through an infrared light box and then be soldered. The temperature of the cell after passing through the infrared is about 220°C, and the time interval is a few seconds. From the end of the soldering to the lamination process, the lamination temperature of the laminator is about 140°C, and the lamination time is generally 20-25 minutes. Infrared treatment may usually cause damage to the passivation film at the edge of the cut. The negative impact of lamination on the passivation effect is mainly that high temperature and long-term lamination will change the fluidity of the film, which may cause the passivation film to decompose and be damaged.

[0034] In the disclosed embodiment, the cut battery cells are oxidatively modified and then coated with a passivation liquid. The passivation liquid adheres more evenly and has stronger adhesion, which can prevent the passivation film from being damaged during infrared and lamination processes.

[0035] In the disclosed embodiment, a passivation film is formed by coating a passivation liquid on the cut edge of the battery cell, thereby passivating the cut edge, reducing the requirements for passivation conditions and simplifying the manufacturing process; by oxidatively modifying the cut battery cell, the passivation liquid is more evenly adhered to the cut edge, thereby increasing the adhesion between the passivation liquid and the cut edge, thereby improving the passivation effect, and at the same time enabling the passivation film to remain stable in the subsequent infrared and lamination processes of the component production line, thereby ensuring the passivation effect.

[0036] The embodiment of the present disclosure does not specifically limit the passivation agent. In the embodiment of the present disclosure, the passivation agent that passivates the cutting edge by oxidation may have a phosphoric acid functional group, a carboxylic acid functional group, or a sulfonic acid functional group.

[0037] In some embodiments, the passivating agent carries a sulfonic acid functional group, a phosphoric acid functional group, or a carboxylic acid functional group.

[0038] In the disclosed embodiment, a passivation solution including a passivating agent with a sulfonic acid functional group is coated on the cut edge of the oxidatively modified cell, and an oxygen (O) atom in the sulfonic acid functional group can be grafted to the silicon (Si) surface of the cut edge to form Si-OR, and the hydrogen (H) atom in the sulfonic acid functional group can form a bond with Si, thereby forming a passivation film on the cut edge. The formation of the passivation film can inhibit the recombination of the exposed silicon dangling bonds on the cut edge, reduce the load, and thus improve the efficiency of the cell.

[0039] The passivating agent with sulfonic acid functional group has low adsorption energy on the cut edge of the oxidatively modified battery cell and is easy to form a passivation film, which is beneficial to improve the passivation effect and increase the stability of the passivation film in the subsequent infrared and lamination processes of the component production line.

[0040] The embodiments of the present disclosure do not specifically limit whether the passivating agent has a sulfonic acid functional group.

[0041] In some embodiments, the passivating agent includes one or more of dodecylbenzenesulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and poly(4-styrenesulfonic acid).

[0042] In some embodiments, the passivation solution further includes an organic solvent, and the organic solvent is selected from one or more of isopropanol, ethylene glycol, ethanol, and deionized water.

[0043] In some embodiments, the organic solvent includes deionized water, and the passivating agent includes poly(4-styrene sulfonic acid); the passivating solution and the deionized water are mixed in a volume ratio of 1:1 to obtain the passivating solution.

[0044] The passivation of the Si surface by poly(4-styrene sulfonic acid) originates from the oxidation of the interface. An O atom in poly(4-styrene sulfonic acid) is grafted onto the Si surface to form Si-OR, and the H atom deviates from the hydroxyl group in poly(4-styrene sulfonic acid) and forms a bond with Si. The formation of the poly(4-styrene sulfonic acid) film inhibits the recombination of the exposed silicon dangling bonds at the cut edge of the cell, reduces recombination, and thus can improve the efficiency of the battery assembly. This structure is relatively easy to form due to the low adsorption energy.

[0045] In the embodiments of the present disclosure, the passivation process of poly(4-styrene sulfonic acid) on the Si surface can be represented by the redox reaction process of formula (1) and formula (2):

[0046]

[0047] In the embodiments of the present disclosure, the oxidation and deoxidation of the Si surface and the lifetime of effective carriers can be controlled through the redox reaction process of formula (1) and formula (2).

[0048] In some embodiments, before the step of coating the passivation solution on the cut edge of the battery cell, the preparation method further includes: a step of preparing the passivation solution.

[0049] In some embodiments, the step of preparing the passivation solution comprises:

[0050] Adding the passivating agent into the organic solvent for mixed dissolution;

[0051] The passivation solution is prepared by magnetic stirring.

[0052] In some embodiments, the passivating agent and the organic solvent are mixed and dissolved in a volume ratio of 1:1, and then magnetically stirred at room temperature (eg, 25° C.) and a humidity of 20%-30% to prepare a passivating solution.

[0053] For example, poly(4-styrene sulfonic acid) and deionized water are mixed and dissolved in a volume ratio of 1:1, and magnetic stirring is performed in an environment of temperature 25° C. and humidity 25% to prepare a passivation solution.

[0054] The disclosed embodiments do not specifically limit how to perform oxidation modification on the cut battery cells.

[0055] In some embodiments, the step of performing oxidation modification on the cut battery cells includes:

[0056] The battery cell is oxidized at high temperature using hydrogen peroxide in a high temperature environment.

[0057] In some embodiments, in the step of oxidatively modifying the battery cell using hydrogen peroxide in a high temperature environment, the high temperature oxidation temperature is 120-160° C., and the high temperature oxidation time is 5-30 min.

[0058] In some embodiments, the high temperature oxidation temperature is 140-150°C, and the high temperature oxidation time is 10-20 minutes. For example, the high temperature oxidation temperature is 120°C, 130°C, 140°C, 150°C or 160°C, and the oxidation time is 10 minutes, 12 minutes, 15 minutes, 18 minutes or 20 minutes.

[0059] For example, the cut battery cells are placed in an oven, two cups of hydrogen peroxide are placed on the left and right sides of the oven, the oven temperature is set to 145°C and the time is 10 minutes, and the cut battery cells are subjected to high-temperature oxidation, so that the cut edges of the battery cells change from hydrophobic to hydrophilic.

[0060] In some embodiments, after the step of coating the passivation solution on the cut edge of the cell, the preparation method further comprises:

[0061] In a preset temperature and humidity environment, the battery cell is placed vertically for a preset time, wherein the cut edge faces downward.

[0062] In the disclosed embodiment, after the passivation liquid is applied, the cut edge of the solar cell is placed vertically, which is conducive to the passivation liquid being evenly attached to the cut edge, thereby improving the passivation effect and simplifying the process.

[0063] The embodiments of the present disclosure do not specifically limit the preset temperature and humidity environment. For example, after applying the passivation solution, the cut side of the solar cell is placed vertically for 10 to 20 minutes in an environment of room temperature (eg, 25° C.) and 20%-30% humidity.

[0064] For example, the coated cell can be placed in Figure 2The device shown is placed in a static state with the cut edge of the cell facing downwards to prevent the passivation liquid from overflowing and sticking. Severe overflowing will cause black edges to form on the cut edge of the cell, which is not conducive to the passivation effect. In addition, by allowing the device to stand still, the passivation liquid is dried while preventing overflowing.

[0065] In some embodiments, in the step of applying the passivation liquid on the cut edge of the cell, the passivation liquid is applied by wiping, spraying or dipping. The passivation agent is finally attached to the cut edge of the cell, ie, the cut edge, in the form of a thin film.

[0066] In some embodiments, in the step of coating the passivation solution on the cut edge of the battery cell, the coating is performed in a single-cell coating manner.

[0067] Single-chip coating means that each cell is coated with passivation solution separately. Single-chip coating is convenient for more uniform coating of passivation solution, and the cells can be separated independently after passivation. Compared with stacked coating, the cells after coating are easy to stick together, and they need to be separated one by one; and the passivation effect of each cell is not as good as that of single-chip coating.

[0068] In some embodiments, after the step of applying the passivation solution, the step further includes: placing the battery cell vertically in a preset temperature and humidity environment for a preset time, wherein the cut edge faces downward.

[0069] The embodiments of the present disclosure do not specifically limit the preset temperature and humidity environment. For example, after applying the passivation solution, the cut side of the solar cell is placed vertically for 10 to 20 minutes in an environment of room temperature (eg, 25° C.) and 20%-30% humidity.

[0070] Figure 2 The device disclosed herein is used to place the passivated battery cells in a static state. After passivation, the cut edges of the battery cells are placed in each slot individually with the cut edges facing downwards, which can prevent flooding and adhesion. Severe flooding will cause black edges to form on the cut edges of the battery cells, which is not conducive to the passivation effect. In addition, by allowing the cells to stand still, flooding is prevented and the passivation liquid is dried at the same time.

[0071] The disclosed embodiment also provides a TOPCon solar cell manufactured according to the above-mentioned method for manufacturing the TOPCon solar cell.

[0072] In some embodiments, a TOPCon solar cell comprises a cut edge and a passivation film attached to the cut edge, wherein the passivation film passivates the cut edge by oxidation.

[0073] In some embodiments, the passivation film is made of a passivating agent having a sulfonic acid functional group.

[0074] In some embodiments, the passivating agent includes one or more of dodecylbenzenesulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, and poly(4-styrenesulfonic acid).

[0075] The present disclosure also provides a TOPCon solar cell, which includes a TOPCon solar cell sheet manufactured according to the above-mentioned method for manufacturing the TOPCon solar cell sheet.

[0076] In order to enable those skilled in the art to more clearly understand the technical solution of the present disclosure, the technical solution of the present disclosure is described in detail below through specific embodiments:

[0077] The half-cell cell in the following embodiments is subjected to PL brightness test before and after infrared and lamination. The conditions of the PL brightness test are 0.2 suns and 0.1 s. The PL brightness test results are read using Image software, and the 7 mm range of the passivation edge is selected for reading.

[0078] Example 1

[0079] A half-cell of a 182mm×182mm TOPCon cell cut by a laser dicing machine was used as the implementation sample.

[0080] Place the cut half-cell in an oven, place two cups of hydrogen peroxide on the left and right sides of the oven, set the oven temperature to 145°C, and start high-temperature oxidation for 30 minutes;

[0081] 5 ml of poly(4-styrene sulfonic acid) and 5 ml of deionized water were fully mixed by magnetic stirring under ambient temperature and humidity conditions to prepare a passivation solution for passivation;

[0082] The prepared passivation solution is evenly applied on the cut surface of the battery cell after high temperature oxidation by brushing;

[0083] The cell coated with the passivation solution is allowed to stand for 20 minutes so that the passivation solution can be evenly attached to the edge of the cell.

[0084] A small module is made up of 5 passivated cells, which are then processed by infrared and lamination, and PL brightness tests are performed before and after the treatment.

[0085] Comparative Example 1

[0086] A small module was made up of 7 unpassivated half-cells, which were then processed by infrared and lamination, and PL brightness tests were performed before and after the treatment.

[0087] Table 1 shows the PL gain of the cut edge of a half-cell cell without passivation solution before and after infrared exposure and before and after lamination.

[0088] Table 1

[0089]

[0090] Table 2 shows the PL gain of the cut edge of the half-cell coated with passivation liquid before and after infrared and before and after lamination. From Table 2, it can be seen that the gain of the edge passivation before and after passivation is 20.88%. After infrared and series welding, the net gain of the small component is 16.56%. Compared with the cell without passivation liquid, the gain of the small component after lamination is about 10%.

[0091] Table 2

[0092]

[0093] Figure 3 The PL brightness of the cut edge of the unpassivated half-cell before and after infrared and lamination. Figure 4 The PL brightness of the cut edge of the passivated half-cell before and after infrared and lamination.

[0094] Based on the data in Table 1-2 and Figure 3-4 It can be seen from the content shown that modifying the cut edge of the cell by high-temperature oxidation not only makes the passivation liquid more evenly distributed on the cut edge of the cell, but also improves the adhesion of the passivation liquid on the cut surface, thereby improving the passivation effect and enabling the cell to withstand subsequent infrared and lamination tests.

[0095] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and should be interpreted only in a general illustrative sense and not for limiting purposes. In some instances, it will be apparent to those skilled in the art that, unless otherwise expressly noted, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments. Therefore, those skilled in the art will appreciate that various changes in form and detail may be made without departing from the scope of the present disclosure as set forth in the appended claims.

Claims

1. A method for preparing a TOPCon solar cell, comprising: Performing oxidation modification on the cut battery cells; A passivation solution is coated on the cut edge of the battery cell to form a passivation film, wherein the passivation solution includes at least one passivating agent, and the passivating agent passivates the cut edge through oxidation.

2. The preparation method according to claim 1, wherein The passivating agent has a sulfonic acid functional group, a phosphoric acid functional group or a carboxylic acid functional group.

3. The preparation method according to claim 2, wherein The passivating agent includes one or more of dodecylbenzenesulfonic acid, 2-acrylamide-2-methyl-1-propanesulfonic acid, and poly (4-styrenesulfonic acid).

4. The preparation method according to any one of claims 1 to 3, wherein The passivation solution also includes an organic solvent, and the organic solvent is selected from one or more of isopropanol, ethylene glycol, ethanol, and deionized water.

5. The preparation method according to claim 4, wherein: The organic solvent includes deionized water, and the passivating agent includes poly(4-styrene sulfonic acid); the passivating solution and the deionized water are mixed in a volume ratio of 1:1 to obtain the passivating solution.

6. The preparation method according to any one of claims 1 to 3, wherein: The step of oxidizing and modifying the cut battery cells includes: The battery cell is oxidized at high temperature using hydrogen peroxide in a high temperature environment.

7. The preparation method according to claim 4, wherein In the step of oxidizing and modifying the battery cell using hydrogen peroxide in a high temperature environment, the high temperature oxidation temperature is 120-160° C. and the high temperature oxidation time is 5-30 minutes.

8. The preparation method according to any one of claims 1 to 3, wherein: After the step of coating the passivation solution on the cut edge of the cell, the preparation method further comprises: In a preset temperature and humidity environment, the battery cell is placed vertically for a preset time, wherein the cut edge faces downward.

9. A TOPCon solar cell, wherein the TOPCon solar cell is obtained according to the method for preparing a TOPCon solar cell according to any one of claims 1 to 8. 10 . A TOPCon solar cell, comprising the TOPCon solar cell sheet according to claim 9 .

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