Solar cell preparation method

Abstract

The invention discloses a solar cell preparation method, and belongs to the technical field of solar cells, and the method comprises the following steps: 1, putting a polycrystalline silicon raw material into an ingot furnace paved with a nucleation source layer, and enabling the polycrystalline silicon raw material to grow into a polycrystalline silicon ingot; and 2, cutting the polycrystalline silicon ingot into square rods by using a diamond wire cutting machine, and then cutting the square rods into polycrystalline silicon chips, The method has the beneficial effects that the solar cell manufactured by the polycrystalline silicon is rich in production raw materials, low in cost, high in conversion efficiency and good in stability, expensive semiconductor materials are greatly saved, and the production cost is greatly reduced under the action of the silicon nitride film. The silicon nitride film has excellent optical performance, for example, the refractive index is close to the optimal refractive index required by a solar cell, the silicon nitride film has good insulativity, compactness, stability and impurity ion masking capacity, and a deposited silicon nitride film contains a large amount of hydrogen and can play a passivation role.

Description

Technical Field

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

[0002] Solar energy is a renewable and clean resource. A solar cell is a photovoltaic semiconductor thin sheet that directly generates electricity using sunlight, also known as a "solar chip" or "photovoltaic cell". As long as it is illuminated by light with a certain illumination intensity, it can instantaneously output voltage and generate current in the case of a circuit. A solar cell is a device that directly converts light energy into electrical energy through the photovoltaic effect or the photochemical effect. Crystalline silicon solar cells operating based on the photovoltaic effect are the mainstream. However, the existing monocrystalline silicon solar cells have a high cost price, it is difficult to significantly reduce their cost, and the process is relatively complex. Summary of the Invention

[0003] (1) Technical Problems to be Solved

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a method for preparing a solar cell, which has the characteristics of rich production raw materials, low cost, high conversion efficiency, and good stability.

[0005] (2) Technical Solutions

[0006] To achieve the above purpose, the present invention provides a method for preparing a solar cell, and the method includes the following steps:

[0007] Step 1: Put the polysilicon raw material into an ingot casting furnace equipped with a nucleation source layer, and grow the polysilicon raw material into a polysilicon ingot;

[0008] Step 2: Use a wire saw squaring machine to cut the polysilicon ingot into square bars, and then cut the square bars into polysilicon wafers;

[0009] Step 3: Chamfer the cut polysilicon wafers, polish their surfaces, and then etch the surfaces of the polysilicon wafers with acid solution;

[0010] Step 4: Place the polysilicon wafers inside an ultrasonic cleaner for cleaning, and perform heat treatment on the cleaned polysilicon wafers;

[0011] Step 5: Place the polysilicon wafers in the prepared etching solution for surface etching, and then perform alkali washing, acid washing, and pure water washing on the polysilicon wafers;

[0012] Step 6: Put the polysilicon wafers inside a diffusion furnace tube to form a relatively stable P-N junction on the surfaces of the polysilicon wafers;

[0013] Step 7: Place the polysilicon wafers inside an etching machine, and etch the edges and corners of the polysilicon wafers through the etching machine;

[0014] Step 8: Place the polysilicon wafer inside a mixed solution of hydrofluoric acid and dilute hydrochloric acid, and etch the phosphosilicate glass on the surface at room temperature.

[0015] Step 9: Place the polysilicon wafer inside an antireflection film deposition device to form a solid film on the surface of the polysilicon wafer.

[0016] Step 10: Apply conductive paste onto the polysilicon wafer through screen printing technology, quickly sinter it through a sintering furnace, and then cut the edges of the polysilicon wafer with a laser.

[0017] Step 11: Test and calculate the photoelectric conversion efficiency of the polysilicon battery to classify it, and then grade and package the qualified batteries and store them in the warehouse.

[0018] Further, the melting temperature of the ingot furnace in Step 1 is controlled between 1420 and 1560 degrees Celsius, and the material at the contact interface between the nucleation source layer and the molten polysilicon raw material is zirconia.

[0019] Further, the thickness of the polysilicon wafer in Step 2 is 125 microns, the polysilicon wafer is a square with a width of 160 mm, and the acid solution in Step 3 is an 18% hydrochloric acid solution.

[0020] Further, the cleaning time in Step 4 is 15 minutes, and the heat treatment is to place the polysilicon wafer at a temperature of 650 - 750 degrees Celsius and heat it for 35 minutes.

[0021] Further, the etching solution in Step 5 is made of 25% hydrofluoric acid, 65% nitric acid solution and deionized water, and the mass ratio is 2:5:1. The alkali wash is a 24% potassium hydroxide solution, and the acid wash is an 18% hydrochloric acid solution.

[0022] Further, the temperature of the diffusion furnace tube in Step 6 is 800 - 900 degrees Celsius, and nitrogen, oxygen and phosphorus oxychloride gases are introduced into the diffusion furnace tube.

[0023] Further, the concentration of the hydrofluoric acid solution in Step 7 is 49%, the concentration of the hydrochloric acid solution is 18%. The solid film in Step 9 is a silicon nitride film with a thickness of about 65 nm, and the internal temperature of the antireflection film deposition device is 500 degrees Celsius.

[0024] Further, the polysilicon wafer is printed three times in Step 10, namely silver-aluminum paste printing on the back of the battery, aluminum paste printing on the back of the battery, and silver paste printing on the front of the battery, and each printing is quickly sintered through a sintering furnace.

[0025] Further, in step eleven, the test is to detect the short - circuit current, open - circuit voltage and fill factor of the polysilicon cell.

[0026] When using the solar cell preparation method of this technical solution, for the solar cell made of polysilicon, its production raw materials are abundant, the cost is low, the conversion efficiency is high, and the stability is good, which greatly saves expensive semiconductor materials. And under the action of the silicon nitride film, it not only has excellent optical properties such as the refractive index close to the optimal refractive index required by the solar cell, but also has good insulation, density, stability and the ability to mask impurity ions. A large amount of hydrogen is contained in the deposited silicon nitride film, which can play a passivation role.

[0027] (3) Beneficial effects

[0028] In summary, the present invention has the following beneficial effects: The solar cell preparation method, by setting... BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for describing the specific embodiments or the prior art. Obviously, the drawings in the following description are only one embodiment of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0030] Figure 1 is the process schematic diagram of the present invention;

[0031] Figure 2 is the process schematic diagram of step ten in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the technical solutions in the specific embodiments of the present invention are clearly and completely described below to further elaborate the present invention. Obviously, the described specific embodiments are only part of the embodiments of the present invention, rather than all of them.

[0033] Example:

[0034] The following combines with the attached... Figure 1-2 Further details of the present invention are provided below.

[0035] Please refer to... Figure 1-2 , the present invention provides a technical solution: A solar cell preparation method, the method includes the following steps:

[0036] Step one: Put the polysilicon raw material into an ingot casting furnace paved with a nucleation source layer, and make the polysilicon raw material grow into a polysilicon ingot;

[0037] Step 2: Use a diamond wire squaring machine to cut the polysilicon ingot into square bars, and then cut the square bars into polysilicon wafers;

[0038] Step 3: Chamfer the cut polysilicon wafers, polish their surfaces, and then etch the surfaces of the polysilicon wafers with acid solution;

[0039] Step 4: Place the polysilicon wafers inside an ultrasonic cleaner for cleaning, and perform heat treatment on the cleaned polysilicon wafers;

[0040] Step 5: Place the polysilicon wafers in the prepared etching solution for surface etching, and then perform alkali washing, acid washing, and pure water washing on the polysilicon wafers;

[0041] Step 6: Place the polysilicon wafers inside a diffusion furnace tube to form a relatively stable P-N junction on the surfaces of the polysilicon wafers;

[0042] Step 7: Place the polysilicon wafers inside an etching machine, and etch the edges and corners of the polysilicon wafers with the etching machine;

[0043] Step 8: Place the polysilicon wafers in a mixed solution of hydrofluoric acid and dilute hydrochloric acid, and etch away the phosphosilicate glass on the surfaces at room temperature;

[0044] Step 9: Place the polysilicon wafers inside an antireflection film deposition device to form a solid film on the surfaces of the polysilicon wafers;

[0045] Step 10: Apply conductive paste onto the polysilicon wafers through screen printing technology, and quickly sinter them through a sintering furnace, and then cut the edges of the polysilicon wafers with a laser;

[0046] Step 11: Test and calculate the photoelectric conversion efficiency of the polysilicon cells to classify them, and then pack and store the qualified cells in different grades.

[0047] Specifically, in Step 1, the melting temperature of the ingot furnace is controlled between 1420 and 1560 degrees Celsius, and the material at the contact interface between the nucleation source layer and the molten polysilicon raw material is zirconia.

[0048] Specifically, the thickness of the polysilicon wafers in Step 2 is 125 micrometers, the polysilicon wafers are squares with a width of 160 millimeters, and the acid solution in Step 3 is an 18% hydrochloric acid solution.

[0049] Specifically, the cleaning time in Step 4 is 15 minutes, and the heat treatment is to place the polysilicon wafers at a temperature of 650 to 750 degrees Celsius and heat them for 35 minutes.

[0050] Specifically, in step five, the etching solution is made of 25% hydrofluoric acid, 65% nitric acid solution and deionized water, and the mass ratio is 2:5:1. The alkali washing is with a 24% potassium hydroxide solution, and the acid washing is with an 18% hydrochloric acid solution.

[0051] Specifically, in step six, the temperature of the diffusion furnace tube is 800 - 900 degrees Celsius, and nitrogen, oxygen and phosphorus oxychloride gas are introduced into the interior of the diffusion furnace tube.

[0052] Specifically, in step seven, the concentration of the hydrofluoric acid solution is 49%, and the concentration of the hydrochloric acid solution is 18%. In step nine, the solid film is a silicon nitride film, with a thickness of about 65 nm, and the internal temperature of the anti-reflection film deposition equipment is 500 degrees Celsius.

[0053] Specifically, in step ten, the polycrystalline silicon wafers are printed three times, namely silver-aluminum paste printing on the back of the cell, aluminum paste printing on the back of the cell, and silver paste printing on the front of the cell, and each printing is followed by rapid sintering in a sintering furnace.

[0054] Specifically, in step eleven, the test is to detect the short-circuit current, open-circuit voltage and fill factor of the polycrystalline silicon cell.

[0055] The working principle of the present invention is as follows: First, put polysilicon raw materials into an ingot casting furnace equipped with a nucleation source layer, and place zirconia on the contact surface of the polysilicon raw materials in the nucleation source layer. Then, control the melting temperature of the ingot casting furnace between 1420 and 1560 degrees Celsius to grow the polysilicon raw materials into polysilicon ingots. Use a diamond wire squaring machine to cut the polysilicon ingots into square bars, and then cut the square bars into square polysilicon wafers with a thickness of 125 micrometers and a width of 160 millimeters. Then, chamfer the cut polysilicon wafers and polish their surfaces. At the same time, corrode the surface of the polysilicon wafers with an 18% hydrochloric acid solution, place the polysilicon wafers inside an ultrasonic cleaner for cleaning for 15 minutes, and place the cleaned polysilicon wafers in an oven at a temperature of 650 - 750 degrees Celsius for heating for 35 minutes. Then, place the polysilicon wafers in the prepared etching solution for surface etching, and then perform alkali washing, acid washing, and pure water washing on the polysilicon wafers. Then, place the polysilicon wafers inside a diffusion furnace tube at a temperature of 800 - 900 degrees Celsius, and introduce nitrogen, oxygen, and phosphorus oxychloride gas inside the diffusion furnace tube to form a relatively stable P-N junction on the surface of the polysilicon wafers. Then, place the polysilicon wafers inside an etching machine, and etch the edges of the polysilicon wafers through the etching machine. Then, place the polysilicon wafers inside a mixed solution of a 49% hydrofluoric acid solution and an 18% hydrochloric acid solution, and corrode the phosphosilicate glass on the surface at room temperature. And place the polysilicon wafers inside an antireflection film deposition device, and at the same time control the temperature inside the antireflection film deposition device to be 500 degrees Celsius to form a silicon nitride film on the surface of the polysilicon wafers, with a thickness of about 65 nm. Then, apply conductive paste on the polysilicon wafers three times through screen printing technology, namely silver-aluminum paste printing on the back of the battery, aluminum paste printing on the back of the battery, and silver paste printing on the front of the battery. And after each printing, quickly sinter through a sintering furnace. Then, cut the edges of the polysilicon wafers through a laser. Then, test and calculate the short-circuit current, open-circuit voltage, and fill factor of the polysilicon battery to obtain the photoelectric conversion efficiency of the polysilicon battery and classify it. Then, grade and package the qualified batteries and store them in the warehouse.

[0056] This specific embodiment is only an explanation of the present invention and is not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A method for preparing a solar cell, characterized in that: The method comprises the following steps: Step 1: placing polycrystalline silicon raw materials into an ingot casting furnace provided with a shaped nucleus source layer, so that the polycrystalline silicon raw materials grow into polycrystalline silicon ingots; Step 2: Using a diamond wire squarer to cut the polysilicon ingot into square bars, and then cutting the square bars into polysilicon wafers; Step 3: Chamfering the cut polycrystalline silicon wafer, polishing its surface, and then corroding the surface of the polycrystalline silicon wafer with acid; Step 4: placing the polycrystalline silicon wafer in an ultrasonic cleaner for cleaning, and heat treating the cleaned polycrystalline silicon wafer; Step 5: Place the polycrystalline silicon wafer in the prepared etching solution for surface etching, and then perform alkali washing, acid washing and pure water washing on the polycrystalline silicon wafer; Step 6: Place the polycrystalline silicon wafer into the diffusion furnace tube to form a relatively stable PN junction on the surface of the polycrystalline silicon wafer; Step 7: Place the polycrystalline silicon wafer inside the etcher, and use the etcher to etch the corners of the polycrystalline silicon wafer; Step 8: Place the polycrystalline silicon wafer in a mixed solution of hydrofluoric acid and dilute hydrochloric acid to etch away the phosphorus silicon glass on the surface at room temperature; Step nine: placing the polycrystalline silicon wafer inside the anti-reflection film deposition equipment, so that a solid film is formed on the surface of the polycrystalline silicon wafer; Step 10: Apply the conductive paste to the polycrystalline silicon wafer by screen printing technology, and quickly sinter it through a sintering furnace, and then cut the edge of the polycrystalline silicon wafer by laser; Step 11: Test and calculate the photoelectric conversion efficiency of polysilicon cells and classify them. Then, package and store the qualified cells in different grades.

2. A method for preparing a solar cell according to claim 1, characterized in that: In the step 1, the melting temperature of the ingot casting furnace is controlled between 1420 and 1560 degrees Celsius, and the material at the contact interface between the nucleation source layer and the molten polysilicon raw material is zirconium dioxide.

3. A method for preparing a solar cell according to claim 1, characterized in that: The thickness of the polysilicon wafer in step 2 is 125 micrometers, the polysilicon wafer is a square with a width of 160 millimeters, and the acid solution in step 3 is 18% hydrochloric acid solution.

4. A method for preparing a solar cell according to claim 1, characterized in that: The cleaning time in step 4 is 15 minutes, and the heat treatment is to heat the polycrystalline silicon wafer at a temperature of 650 to 750 degrees Celsius for 35 minutes.

5. A method for preparing a solar cell according to claim 1, characterized in that: In the step 5, the etching solution is made of 25% hydrofluoric acid, 65% nitric acid solution and deionized water, and the mass ratio is 2:5:

1. The alkaline washing is 24% potassium hydroxide solution, and the acid washing is 18% hydrochloric acid solution.

6. A method for preparing a solar cell according to claim 1, characterized in that: In step six, the temperature of the diffusion furnace tube is 800-900 degrees Celsius, and nitrogen, oxygen and phosphorus oxychloride gas are introduced into the diffusion furnace tube.

7. A method for preparing a solar cell according to claim 1, characterized in that: The concentration of the hydrofluoric acid solution in step seven is 49%, the concentration of the hydrochloric acid solution is 18%, the solid film in step nine is a silicon nitride film with a thickness of about 65 nm, and the internal temperature of the anti-reflection film deposition equipment is 500 degrees Celsius.

8. A method for preparing a solar cell according to claim 1, characterized in that: In the step 10, the polysilicon wafer is printed three times in total, namely, printing with silver-aluminum paste on the back of the battery, printing with aluminum paste on the back of the battery, and printing with silver paste on the front of the battery, and after each printing, it is quickly sintered in a sintering furnace.

9. A method for preparing a solar cell according to claim 1, characterized in that: The test in step 11 is to detect the short-circuit current, open-circuit voltage and fill factor of the polycrystalline silicon battery.

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