Solar cell preparation method and solar cell

Abstract

The invention provides a preparation method of a solar cell and the solar cell, and relates to the technical field of solar cells. The preparation method of the solar cell comprises the following steps: providing a quasi-heterojunction solar cell, forming masks on a first transparent conductive layer and a second transparent conductive layer of the quasi-heterojunction solar cell, and patterning the masks, the patterned mask exposes to-be-electroplated areas on the first transparent conductive layer and the second transparent conductive layer, micro-etching is carried out on the first transparent conductive layer and the second transparent conductive layer in the to-be-electroplated areas, and then the micro-etched first transparent conductive layer and the micro-etched second transparent conductive layer in the to-be-electroplated areas are preprocessed; and copper electrodes are electroplated on the to-be-electroplated areas of the first transparent conductive layer and the second transparent conductive layer after pretreatment. According to the preparation method of the solar cell, the binding force between the copper electrode and the transparent conductive layer is increased while the cell efficiency is not responded, and the electrode is prevented from falling off.

Description

Technical Field

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

[0002] A solar cell is a type of solar cell that produces a photoelectric effect by forming a junction between two different semiconductor materials. These two semiconductor materials have different physical properties such as band gaps and electron affinities. Through a reasonable combination, they can effectively improve the absorption of sunlight and the photoelectric conversion efficiency of the cell. At present, the most pressing problem in the industrialization of heterojunction solar cells is the high production cost, and about 30% of the production cost of solar cells is caused by a large amount of expensive low-temperature silver paste used in the screen printing process. Therefore, an alternative metallization technology that maintains good cell performance at a low cost has a high technical value. Copper is considered to be an ideal alternative metal contact for silicon solar cells due to its high conductivity and low price. It is reported that copper metallization technology can overcome the limitations of screen printing technology, and has the advantages of low cost, high efficiency, low contact resistivity, etc., and can be used in a variety of technical paths such as TopCon, HJT, and BC. However, the preparation process of solar cells with copper electroplating includes four steps: preparation of seed layer, patterning, electroplating, and post-processing. Among them, the preparation of seed layer is costly and complicated. Direct electroplating on TCO (TCO includes various types, such as ITO, TTO, ICO, IWO, etc.) has a physical contact with the coating and the TCO layer, and the adhesion is mainly van der Waals force, which can easily cause the electrode to fall off. Summary of the invention

[0003] An object of the first aspect of the present invention is to provide a method for preparing a solar cell, so as to solve the problem that the electrodes of the solar cell are easy to fall off in the prior art.

[0004] The second aspect of the present invention aims to provide a solar cell prepared by the above-mentioned method for preparing a solar cell.

[0005] In particular, the present invention also provides a method for preparing a solar cell, the method comprising:

[0006] A quasi-heterojunction solar cell is provided; wherein the quasi-heterojunction solar cell comprises a silicon substrate, a first intrinsic amorphous silicon layer, a first doped layer, and a first transparent conductive layer arranged on the front surface of the silicon substrate, and a second intrinsic amorphous silicon layer, a second doped layer, and a second transparent conductive layer arranged on the back surface of the silicon substrate;

[0007] Forming a mask on the first transparent conductive layer and the second transparent conductive layer of the quasi-heterojunction solar cell, and patterning the mask, wherein the patterned mask exposes the areas to be electroplated of the first transparent conductive layer and the second transparent conductive layer;

[0008] Micro-etching the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated;

[0009] Pre-treating the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated after micro-etching;

[0010] Electroplating copper on the pre-treated first transparent conductive layer and the second transparent conductive layer in the to-be-plated area;

[0011] The quasi-heterojunction solar cell is post-processed after copper electroplating.

[0012] Optionally, the step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated after micro-etching includes:

[0013] Performing electrochemical reduction pretreatment on the first transparent conductive layer and the second transparent conductive layer after micro-etching;

[0014] The step of performing electrochemical reduction pretreatment comprises:

[0015] The first transparent conductive layer and the second transparent conductive layer after micro-etching are used as cathodes, and the titanium mesh, indium plate or tin plate is used as anodes, and are placed in electrochemical reduction solution, and a direct current of 0-2A is passed through to react for 10-120s.

[0016] Optionally, the electrochemical reduction solution is selected from one or more combinations of 0.01-1 mol / L sodium citrate, 0.01-1M sodium sulfate or 0.01-1 mol / L sodium sulfate decahydrate.

[0017] Optionally, when the first transparent conductive layer and the second transparent conductive layer are ITO, the anode is an indium plate, and the equation of the electrochemical reduction reaction is:

[0018] In2O3+3H2O+6e - =2In+6OH - (1)

[0019] 2H2O+2e - =H2↑+2OH - (2).

[0020] Optionally, when the first transparent conductive layer and the second transparent conductive layer are TTO, the anode is a tin plate, and the equation of the electrochemical reduction reaction is:

[0021] SnO2+2H2O+4e - →Sn+4OH - (3)

[0022] 4OH - -4e - →O2+2H2O (4)

[0023] SnO2→Sn+O2 (5).

[0024] Optionally, the step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated after micro-etching includes:

[0025] Chemically pre-treating the first transparent conductive layer and the second transparent conductive layer after micro-etching to form a mixed metal layer;

[0026] The step of performing chemical pretreatment to form a mixed metal layer comprises:

[0027] Prepare chemical pretreatment solutions;

[0028] The first transparent conductive layer and the second transparent conductive layer after micro-etching are placed in the chemical pretreatment solution, a stabilizer is added, and the reaction is carried out for 3 to 12 minutes.

[0029] Optionally, the step of preparing a chemical pretreatment solution comprises:

[0030] Add 0.1-1 mol / L FeSO4·7H2O and zinc powder to 0.1-1 mol / L sodium citrate solution and sonicate for 5-10 min;

[0031] After centrifugation, the supernatant was collected;

[0032] The pH value of the supernatant was adjusted to 1-8 with concentrated sulfuric acid.

[0033] Optionally, the stabilizer is citric acid, acetic acid, lactic acid, or sulfurous acid with a pH value of 2 to 5.

[0034] Optionally, the step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated after micro-etching includes:

[0035] The first transparent conductive layer and the second transparent conductive layer after micro-etching are pre-treated by electroplating, and a metal of the same family as the first transparent conductive layer and the second transparent conductive layer is electroplated.

[0036] Optionally, the electroplating process includes:

[0037] A light-shielding area is provided at the entrance and the exit of the electroplating tank, wherein a sensor, a conductive brush and a light source are provided in the light-shielding area, and a conductive brush and a light source are provided in the non-light-shielding area;

[0038] When it is detected that the target object is completely located in the electroplating tank from the entrance, the conductive brush and the light source in the light-shielding area and the non-light-shielding area are turned on at the same time; or when it is detected that the target object moves from the exit to start to leave the electroplating tank, the conductive brush and the light source in the light-shielding area and the non-light-shielding area are turned off at the same time.

[0039] Optionally, the size of the light-shielding area at the entrance of the electroplating tank is greater than or equal to the size of the target object;

[0040] The size of the light-shielding area at the outlet of the electroplating tank is greater than or equal to the size of the target object.

[0041] Optionally, a drying component is disposed above each of the conductive brushes, wherein the drying component is located 2-5 cm above the corresponding conductive brush.

[0042] Optionally, the step of micro-etching the first transparent conductive layer and the second transparent conductive layer in the electroplating area includes:

[0043] The quasi-heterojunction solar cell after the mask patterning process is placed in a micro-etching solution for immersion; wherein the micro-etching solution includes one selected from sulfuric acid, phosphoric acid, citric acid, methanesulfonic acid, and ammonia water.

[0044] In particular, the present invention also provides a solar cell, which is prepared according to the above-mentioned method for preparing a solar cell.

[0045] In the preparation method of the solar cell of the present scheme, a mask is formed on the transparent conductive layer of the quasi-heterojunction solar cell sheet, and the mask is patterned, the patterned mask exposes the areas to be electroplated of the first transparent conductive layer and the second transparent conductive layer, the transparent conductive layer in the areas to be electroplated is micro-etched, the micro-etched transparent conductive layer is pre-treated, and copper is electroplated on the pre-treated transparent conductive layer, so as to increase the bonding force between the copper electrode and the transparent conductive layer without affecting the battery efficiency, and prevent the electrode from falling off.

[0046] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0048] Figure 1 is a schematic structural diagram of a solar cell according to a specific embodiment of the present invention;

[0049] Figure 2 It is a schematic structural diagram of an electroplating device according to a specific embodiment of the present invention.

[0050] Description of reference numerals:

[0051] Entrance - 100; Exit - 200; Sensor - 300; Conductive brush - 400; Light source - 500; Plating tank - 600; Dark box - 700; Target - 800. DETAILED DESCRIPTION

[0052] In the description of this embodiment, it should be understood that the terms "length", "width", "height", "up", "down", "left", "right", "vertical", "horizontal", "bottom", "inside" and "outside" etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0053] A method for preparing a solar cell is disclosed. Specifically, the method for preparing a solar cell may include:

[0054] Step S100, providing a quasi-heterojunction solar cell; wherein the quasi-heterojunction solar cell comprises a silicon substrate, a first intrinsic amorphous silicon layer, a first doped layer, and a first transparent conductive layer arranged on the front surface of the silicon substrate, and a second intrinsic amorphous silicon layer, a second doped layer, and a second transparent conductive layer arranged on the back surface of the silicon substrate;

[0055] Step S200, forming a mask on the first transparent conductive layer and the second transparent conductive layer of the quasi-heterojunction solar cell, and patterning the mask, wherein the patterned mask exposes the areas to be electroplated of the first transparent conductive layer and the second transparent conductive layer;

[0056] Step S300, micro-etching the first transparent conductive layer and the second transparent conductive layer in the electroplating area;

[0057] Step S400, pre-treating the first transparent conductive layer and the second transparent conductive layer in the electroplating area after micro-etching;

[0058] Step S500, electroplating copper on the pre-treated first transparent conductive layer and the second transparent conductive layer in the to-be-plated area;

[0059] Step S600, post-processing the quasi-heterojunction solar cell after copper electroplating.

[0060] Specifically, in the method for preparing a solar cell of this embodiment, a mask is formed on the transparent conductive layer of the quasi-heterojunction solar cell, and the mask is patterned, wherein the patterned mask exposes the areas to be electroplated of the first transparent conductive layer and the second transparent conductive layer.

[0061] The transparent conductive layer in the area to be electroplated exposed by the patterned mask is micro-etched, the micro-etched transparent conductive layer is pre-treated, and copper is electroplated on the pre-treated transparent conductive layer. This increases the bonding force between the copper electrode and the transparent conductive layer without affecting the battery efficiency, thereby preventing the electrode from falling off.

[0062] As a specific embodiment of the present invention, the step S300 of the present embodiment of micro-etching the first transparent conductive layer and the second transparent conductive layer in the electroplating area may include:

[0063] The quasi-heterojunction solar cell after the mask patterning process is placed in a micro-etching solution for immersion. The micro-etching solution may include one selected from sulfuric acid, phosphoric acid, citric acid, methanesulfonic acid, and ammonia water.

[0064] As a specific embodiment of the present invention, in step S400 of this embodiment, the step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the electroplating area after micro-etching may include:

[0065] The first transparent conductive layer and the second transparent conductive layer after micro-etching are pre-treated by electrochemical reduction.

[0066] The steps of performing electrochemical reduction pretreatment include:

[0067] The first transparent conductive layer and the second transparent conductive layer after micro-etching are used as cathodes, and the titanium mesh, indium plate or tin plate is used as anodes, and are placed in electrochemical reduction solution, and a direct current of 0-2A is passed through to react for 10-120s.

[0068] Specifically, the direct current passed during the electrochemical reduction pretreatment of this embodiment may be 0.5 V, 1 V, 1.5 V, 1.8 V or 2 V. The reaction time may also be 10 s, 20 s, 40 s, 50 s, 60 s, 80 s, 100 s or 120 s.

[0069] Specifically, in this embodiment, indium or tin metal can be obtained on the transparent conductive layer after micro-etching by electrochemical reduction pretreatment, and then these indium or tin metals can be used as seed layers, and then copper electrodes are electroplated on these seed layers to increase the bonding strength of the electrodes. In this embodiment, the seed layer is obtained by electrochemical reduction pretreatment, and the in-situ seed layer technology is used to simplify the full solution-based plating process, without the need for full-area seed layer deposition and subsequent etching reaction steps, effectively reducing the cost of the copper metallization preparation process of heterojunction solar cells.

[0070] As a specific embodiment of the present invention, the electrochemical reduction solution of this embodiment is selected from one or more combinations of 0.01-1 mol / L sodium citrate, 0.01-1 mol / L sodium sulfate or 0.01-1 mol / L sodium sulfate decahydrate.

[0071] As a specific embodiment of the present invention, in this embodiment, when the first transparent conductive layer and the second transparent conductive layer are ITO, the anode is an indium plate, and the equation of the electrochemical reduction reaction at this time is:

[0072] In2O3+3H2O+6e - =2In+6OH - (1)

[0073] 2H2O+2e - =H2↑+2OH - (2).

[0074] As a specific embodiment of the present invention, in this embodiment, when the first transparent conductive layer and the second transparent conductive layer are TTO, the anode is a tin plate, and the equation of the electrochemical reduction reaction at this time is:

[0075] SnO2+2H2O+4e - →Sn+4OH - (3)

[0076] 4OH - -4e - →O2+2H2O(4)

[0077] SnO2→Sn+O2(5).

[0078] Specifically, the electrochemical reaction in this embodiment is mainly to reduce the metal elements in the transparent conductive layer to form metal atoms through the reaction of chemical solutions with the substances in the transparent conductive layer, and then use them as a seed layer, and electroplate copper on the seed layer to improve the adhesion of the copper electrode.

[0079] As a specific embodiment of the present invention, in step S400 of this embodiment, the step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the electroplating area after micro-etching includes:

[0080] Chemically pre-treating the first transparent conductive layer and the second transparent conductive layer after micro-etching to form a mixed metal layer;

[0081] The steps of performing chemical pretreatment to form a mixed metal layer include:

[0082] Prepare chemical pretreatment solutions;

[0083] The first transparent conductive layer and the second transparent conductive layer after micro-etching are placed in a chemical pretreatment solution, a stabilizer is added, and the reaction is carried out for 3 to 12 minutes.

[0084] Specifically, the steps of preparing the chemical pretreatment solution in this embodiment include:

[0085] Add 0.1-1M FeSO4·7H2O and zinc powder to 0.1-1mol / L sodium citrate solution and sonicate for 5-10min;

[0086] After centrifugation, the supernatant was collected;

[0087] The pH value of the supernatant was adjusted to 1-8 with concentrated sulfuric acid.

[0088] The chemical pretreatment solution is to add FeSO4·7H2O and zinc powder to the sodium citrate solution and perform ultrasound, which is beneficial to the Fe 3+ ions are reduced to Fe 2+ The color of the chemical pretreatment solution will also change from light yellow to light green. The concentration of the sodium citrate solution in this embodiment is 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L.

[0089] Specifically, the stabilizer of this embodiment can be citric acid, acetic acid, lactic acid, sulfurous acid, etc. with a pH value of 2 to 5.

[0090] Specifically, the pretreatment step of this embodiment is to perform chemical pretreatment, and the chemical pretreatment is further to react with a chemical pretreatment solution, and finally Fe 2+ , zinc powder and iron obtained by the reaction, that is, there is a mixed metal layer on the transparent conductive layer. After the pretreatment is completed, the mixed metal is directly used as a seed layer for electroplating a copper electrode, thereby increasing the adhesion between the copper electrode and the transparent conductive layer.

[0091] As another specific embodiment of the present invention, in step S400 of this embodiment, the step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the electroplating area after micro-etching may include:

[0092] The first transparent conductive layer and the second transparent conductive layer after micro-etching are pre-treated by electroplating, and metals of the same family as the first transparent conductive layer and the second transparent conductive layer are electroplated.

[0093] Specifically, in this embodiment, a metal of the same family as the material of the transparent conductive layer is electroplated on the micro-etched transparent conductive layer. On the one hand, the metal of the same family has good adhesion to the transparent conductive layer. On the other hand, the metal can be used as a seed layer for electroplating copper electrodes and has good adhesion to the copper electrodes. Therefore, the adhesion between the copper electrodes and the transparent conductive layer can be increased to prevent the copper electrodes from falling off.

[0094] As a specific embodiment of the present invention, the process of electroplating pretreatment and copper electroplating in this embodiment includes:

[0095] A light-shielding area is provided at the entrance 100 and the exit 200 of the electroplating tank 600, wherein the sensor 300, the conductive brush 400 and the light source 500 are provided in the light-shielding area, and the conductive brush 400 and the light source 500 are provided in the non-light-shielding area;

[0096] When it is detected that the target object 800 is completely located in the electroplating tank 600 from the entrance 100, the conductive brush 400 and the light source 500 in the light-shielding area and the non-light-shielding area are turned on at the same time; or when it is detected that the target object 800 moves from the exit 200 to start leaving the electroplating tank 600, the conductive brush 400 and the light source 500 in the light-shielding area and the non-light-shielding area are turned off at the same time.

[0097] Specifically, the electroplating process of this embodiment includes both the electroplating process of the electroplated copper electrode and the electroplating process of the same family metal in the pretreatment. Specifically, the electroplating process of the electroplated copper electrode generally lasts about 20 minutes, while the electroplating pretreatment process of the electroplated transition metal lasts about 2 minutes. Of course, the electroplating time can be changed according to the actual situation, and can be any time from 0 to 20 minutes. During the electroplating process, the process of the battery cell entering and exiting will cause part of the battery cell to be outside, which will lead to uneven final electroplating. If the pretreatment electroplating part is uniform, it will affect the subsequent electroplating of the copper electrode, resulting in poor bonding strength of the copper electrode and falling off. The uneven electroplating of the copper electrode will cause its current transmission capacity to be unable to be guaranteed.

[0098] Specifically, when the cell sees light, the PN junction of the silicon wafer is opened, making the NP surface of the silicon wafer conductive. During the electroplating process, light-shielding areas are set in front and behind the electroplating tank 600, and the light source 500 and the conductive brush 400 are turned on and powered only when the target object 800 enters the electroplating tank 600, and when the target object 800 begins to leave the electroplating tank 600, the power of the light source 500 and the conductive brush 400 are turned off, so as to ensure that the target object 800 always enters the electroplating tank 600 during the electroplating process, thereby ensuring the uniformity of the electroplating.

[0099] Specifically, the light-shielding area in this embodiment can be a dark box 700, and the dark box 700 is set in front of and behind the electroplating tank 600. In order to turn on the power supply when the target object 800 completely enters the electroplating tank 600 or turn off the power supply when it starts to leave the electroplating tank 600, the size of the light-shielding area (i.e., the dark box) at the entrance 100 of the electroplating tank 600 is greater than or equal to the size of the target object 800. The size of the light-shielding area (i.e., the dark box) at the exit 200 of the electroplating tank 600 is greater than or equal to the size of the target object 800.

[0100] Specifically, the size of the dark box 700 of this embodiment (the size in the direction of movement) is basically twice the size of the target object 800, half of which is inside the electroplating tank 600 and half is outside the electroplating tank 600, ensuring that the target object 800 is always completely located in the electroplating tank 600 during the electroplating process, thereby improving the uniformity of the electroplating.

[0101] As a specific embodiment of the present invention, a plurality of sensors 300 are arranged inside and outside the dark box 700 of this embodiment. The position of the target object 800 can be accurately obtained through the sensors 300, so that the light sources 500 inside and outside the dark box 700 are turned on only when the target object 800 completely enters the electroplating tank 600, and the light sources 500 and the conductive brush 400 are turned off in other cases.

[0102] Specifically, each dark box of the present embodiment may include 2-4 conductive brushes 400. The more conductive brushes 400 there are, the more uniform the electroplating is.

[0103] Specifically, in this embodiment, a drying component is arranged above each conductive brush 400, wherein the drying component is located 2-5 cm above the corresponding conductive brush 400. The drying component may be an air knife, and the gas flow rate of the drying component is controlled at 0-100 l / min, and the blowing angle is 0-90°. The gas blowing can ensure that the conductive brush 400 is dry, reduce the defective rate of silicon wafers, and extend the equipment maintenance cycle.

[0104] As a specific embodiment of the present invention, this embodiment provides a solar cell, which is prepared according to the above method for preparing a solar cell. The electrode and the transparent conductive layer of the solar cell of this embodiment are not easy to fall off.

[0105] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A method for preparing a solar cell, characterized in that: The method comprises: A quasi-heterojunction solar cell is provided; wherein the quasi-heterojunction solar cell comprises a silicon substrate, a first intrinsic amorphous silicon layer, a first doped layer, and a first transparent conductive layer arranged on the front surface of the silicon substrate, and a second intrinsic amorphous silicon layer, a second doped layer, and a second transparent conductive layer arranged on the back surface of the silicon substrate; Forming a mask on the first transparent conductive layer and the second transparent conductive layer of the quasi-heterojunction solar cell, and patterning the mask, wherein the patterned mask exposes the areas to be electroplated of the first transparent conductive layer and the second transparent conductive layer; Micro-etching the first transparent conductive layer and the second transparent conductive layer in the electroplating area; Pre-treating the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated after micro-etching; Electroplating copper on the pre-treated first transparent conductive layer and the second transparent conductive layer in the to-be-plated area; The quasi-heterojunction solar cell is post-processed after copper electroplating.

2. The method for preparing a solar cell according to claim 1, characterized in that: The step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated after micro-etching comprises: Performing electrochemical reduction pretreatment on the first transparent conductive layer and the second transparent conductive layer after micro-etching; The step of performing electrochemical reduction pretreatment comprises: The first transparent conductive layer and the second transparent conductive layer after micro-etching are used as cathodes, and the titanium mesh, indium plate or tin plate is used as anodes, and are placed in electrochemical reduction solution, and a direct current of 0-2A is passed through to react for 10-120s.

3. The method for preparing a solar cell according to claim 2, characterized in that: The electrochemical reduction solution is selected from one or more combinations of 0.01-1 mol / L sodium citrate, 0.01-1 mol / L sodium sulfate or 0.01-1 mol / L sodium sulfate decahydrate, indium pyrophosphate, indium sulfate, and stannous sulfate.

4. The method for preparing a solar cell according to claim 2, characterized in that: When the first transparent conductive layer and the second transparent conductive layer are ITO, the anode is an indium plate, and the equation of the electrochemical reduction reaction is: In2O3+3H2O+6e - =2In+6OH - (1) <h2 style=";text-align:left;direction:ltr">2H2O+2e<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> =H2↑+2OH<h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> (2) 5. The method for preparing a solar cell according to claim 2, characterized in that: When the first transparent conductive layer and the second transparent conductive layer are TTO, the anode is a tin plate, and the equation of the electrochemical reduction reaction is: SnO2+2H2O+4e - →Sn+4OH - (4) 4OH - -4e - →O2+2H2O (5) SnO2→Sn+O2 (6).

6. The method for preparing a solar cell according to claim 1, characterized in that: The step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated after micro-etching comprises: Chemically pre-treating the first transparent conductive layer and the second transparent conductive layer after micro-etching to form a mixed metal layer; The step of performing chemical pretreatment to form a mixed metal layer comprises: Prepare chemical pretreatment solutions; The first transparent conductive layer and the second transparent conductive layer after micro-etching are placed in the chemical pretreatment solution, a stabilizer is added, and the reaction is carried out for 3 to 12 minutes.

7. The method for preparing a solar cell according to claim 6, characterized in that: The step of preparing the chemical pretreatment solution comprises: Add 0.1-1 mol / L FeSO4·7H2O and zinc powder to 0.1-1 mol / L sodium citrate solution and sonicate for 5-10 min; After centrifugation, the supernatant was collected; The pH value of the supernatant is adjusted to 1-8 with concentrated sulfuric acid to stabilize the pH value of the solution; and / or, The stabilizer is a citric acid solution, acetic acid, lactic acid, or sulfurous acid with a pH value of 2 to 5.

8. The method for preparing a solar cell according to claim 1, characterized in that: The step of pre-treating the first transparent conductive layer and the second transparent conductive layer in the area to be electroplated after micro-etching comprises: The first transparent conductive layer and the second transparent conductive layer after micro-etching are pre-treated by electroplating, and a metal of the same family as the first transparent conductive layer and the second transparent conductive layer is electroplated.

9. The method for preparing a solar cell according to claim 1 or 8, characterized in that: The process of electroplating pretreatment and / or electroplating copper includes: A light-shielding area is provided at the entrance and the exit of the electroplating tank, wherein a sensor, a conductive brush and a light source are provided in the light-shielding area, and a conductive brush and a light source are provided in the non-light-shielding area; When it is detected that the target object is completely located in the electroplating tank from the entrance, the conductive brush and the light source in the light-shielding area and the non-light-shielding area are turned on at the same time; when it is detected that the target object moves from the exit to start to leave the electroplating tank, the conductive brush and the light source in the light-shielding area and the non-light-shielding area are turned off at the same time.

10. The method for preparing a solar cell according to claim 9, characterized in that: The size of the light-shielding area at the entrance of the electroplating tank is greater than or equal to the size of the target object; The size of the light-shielding area at the outlet of the electroplating tank is greater than or equal to the size of the target object; and / or, A drying component is arranged above each of the conductive brushes, wherein the drying component is located 2-5 cm above the corresponding conductive brush.

11. The method for preparing a solar cell according to claim 1, characterized in that: The step of micro-etching the first transparent conductive layer and the second transparent conductive layer in the electroplating area comprises: The quasi-heterojunction solar cell after the mask patterning process is placed in a micro-etching solution for immersion; wherein the micro-etching solution includes one selected from sulfuric acid, phosphoric acid, citric acid, methanesulfonic acid, and ammonia water.

12. A solar cell, characterized in that: The solar cell is prepared according to the method for preparing the solar cell according to claims 1-15.

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