Preparation method of photovoltaic crystalline silicon texturing agent

Abstract

The invention discloses a preparation method of a photovoltaic crystalline silicon texturing agent, which comprises the following steps: step 1, preparing alkali liquor, adding xylitol and mannuronic acid into a KOH solution according to a ratio of (1-1.5): (1.5-2), heating, stirring, and cooling for later use; the beneficial effects are that the xylitol and the mannuronic acid are mixed according to a specific ratio to prepare the alkali liquor of the texturing agent, and the texturing particles are added into the alkali liquor, so that on one hand, the photovoltaic crystalline silicon texturing agent does not have any toxic or side effect during use, and is more convenient to operate; on one hand, the photovoltaic crystalline silicon texturing agent can effectively reduce the stimulation of the photovoltaic crystalline silicon texturing agent to a human body during use and ensure the health of the human body, on the other hand, the interaction speed of alkali liquor and the surface of a photovoltaic crystalline silicon wafer can be effectively accelerated under the action of the texturing particles, the texturing speed of the photovoltaic crystalline silicon wafer in the texturing agent is accelerated, and the texturing particles can be repeatedly utilized, so that the texturing agent is environment-friendly and energy-saving. Therefore, the use cost of the photovoltaic crystalline silicon texturing agent is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of crystalline silicon surface texturing, and in particular to a method for preparing a photovoltaic crystalline silicon texturing agent. Background Art

[0002] Solar cells are devices that use the photoelectric conversion effect to convert light energy into electrical energy. They have been vigorously developed due to their safety, pollution-free, and no geographical restrictions. Crystalline silicon solar cells account for more than 80% of the entire photovoltaic industry due to their mature technology and high conversion efficiency. High efficiency and low cost have always been the constant pursuit of the photovoltaic industry, and surface reflectivity is one of the important factors affecting the photoelectric conversion efficiency of solar cells. Solar cell surface texturing technology can effectively reduce the surface reflectivity of solar cells. Crystalline silicon solar cells can be divided into single crystal silicon cells and polycrystalline silicon cells. Their production processes are basically similar, and the biggest difference lies in the surface texturing method. Among them, single crystal silicon solar cells mainly use the anisotropic corrosion characteristics of single crystal silicon wafers in alkaline solutions to construct random pyramid light-trapping structures on the surface of silicon wafers, while polycrystalline silicon wafers are prepared by hydrofluoric acid and nitric acid corrosion to produce pit light-trapping structures.

[0003] At present, the preparation of photovoltaic crystalline silicon texturing agent is mainly achieved by adding alcohol texturing additives such as isopropyl alcohol and ethanol and alcohol-free texturing additives to potassium hydroxide solution. Although the photovoltaic crystalline silicon texturing agent prepared by the above method can meet the texturing needs of photovoltaic crystalline silicon wafers, on the one hand, due to the strong volatility of additives such as isopropyl alcohol and ethanol, the texturing process has large losses and requires frequent refilling, which is inconvenient to operate and is not environmentally friendly. On the other hand, the alcohol-free additives are usually chemical liquids including a variety of complex organic substances (such as tetramethylammonium hydroxide, vinyl pyrrolidone-vinyl imidazole copolymer, glutathione and chondroitin sulfate, etc.), most of which are toxic and expensive, greatly increasing the texturing cost; and the organic residues of the single crystal silicon wafers after texturing are not easy to remove, requiring an additional cumbersome cleaning process, and the waste liquid after cleaning will also increase the generation process and increase the environmental protection treatment cost, seriously affecting the production efficiency of single crystal silicon solar energy. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a photovoltaic crystalline silicon texturing agent in order to solve the above problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] A method for preparing a photovoltaic crystalline silicon texturing agent comprises the following steps:

[0007] Step 1: prepare alkaline solution, add xylitol and mannuronic acid into KOH solution in a ratio of (1-1.5):(1.5-2), heat and stir, then cool for later use;

[0008] Step 2: Preparation of velvet particles: fluorine-containing polymers, alkali-resistant organic polymers, and inorganic non-metallic particles are mixed in a specific ratio to obtain velvet particles for later use.

[0009] Step 3: Preparation of photovoltaic crystalline silicon texturing agent, adding the texturing particles prepared in step 2 to the alkaline solution prepared in step 1, and mixing and stirring at a temperature of 75-85°C to prepare the photovoltaic crystalline silicon texturing agent.

[0010] Furthermore, the optimal ratio of xylitol to mannuronic acid in step 1 is 1.2:1.5, the heating temperature in step 1 is 60-80° C., and the reaction time is 3-8 hours.

[0011] Furthermore, the texturing particles in step 2 are made of fluorine-containing polymer, alkali-resistant organic polymer, and inorganic non-metallic particles in a ratio of 1:1:0.5, and the particle size of the texturing particles is 100-400 μm.

[0012] Furthermore, in step 2, the fluorine polymer is prepared by mixing polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, and tetrafluoroethylene-hexafluoropropylene copolymer in a ratio of 2:1:1.

[0013] Furthermore, the alkali corrosion resistant organic polymer in step 2 is ultra-high molecular weight polyethylene, and the inorganic non-metallic particles in step 2 are nano-silicon dioxide particles.

[0014] Furthermore, in step 3, the method for obtaining kinetic energy of the texturing particles is by stirring.

[0015] Furthermore, the method of using the photovoltaic crystalline silicon texturing agent is as follows: first, a layer of continuous microscopic V-grooves with a depth of 3.2-3.5μm is opened on the surface of the photovoltaic crystalline silicon wafer to be texturized, and the photovoltaic crystalline silicon wafer is then added to the texturing agent and reacted at 70-90°C for 5-10 minutes. Then, the photovoltaic crystalline silicon wafer after the reaction is simply cleaned in a dark place to complete the texturing process on the surface of the photovoltaic crystalline silicon wafer. Studies have found that the V-groove structure has good omnidirectionality, that is, when the incident angle of sunlight varies within a large range, the reflectivity of the V-groove structure can always be maintained within a low range, thereby achieving good light absorption under different lighting conditions. Therefore, the V-groove structure is considered to be a photovoltaic crystalline silicon wafer velvet structure that is more suitable for practical applications. Therefore, a layer of microscopic V-grooves is pre-opened on the surface of the photovoltaic crystalline silicon wafer before texturing to ensure that the surface of the photovoltaic crystalline silicon wafer after the final texturing is a V-shaped structure.

[0016] Furthermore, the non-ionic surfactants xylitol and mannuronic acid in the alkali solution of the photovoltaic crystalline silicon texturing agent are outstanding representatives of sugar ether surfactants and are a new generation of green surfactants, which makes the photovoltaic crystalline silicon texturing agent less irritating to the human body when used and can be quickly biodegraded; at the same time, the texturing process of the texturing particles in the photovoltaic crystalline silicon texturing agent is mainly through the collision of the texturing particles with the hydrogen bubbles generated in the texturing process, so that the hydrogen bubbles are destroyed or split, and at the same time, the texturing particles desorb the hydrogen bubbles attached to the surface of the single crystal silicon wafer, thereby realizing the texturing of the surface of the single crystal silicon wafer.

[0017] The beneficial effects of the present invention are:

[0018] The present invention prepares an alkali solution of a texturing agent by mixing xylitol and mannuronic acid in a specific ratio, and adds texturing particles into the alkali solution. On the one hand, the photovoltaic crystalline silicon texturing agent has no toxic side effects when used, and the operation is more convenient. It can also effectively reduce the stimulation of the photovoltaic crystalline silicon texturing agent to the human body when used, thereby ensuring the health of the human body. On the other hand, under the action of the texturing particles, the interaction speed between the alkali solution and the surface of the photovoltaic crystalline silicon wafer can be effectively accelerated, and the texturing speed of the photovoltaic crystalline silicon wafer in the texturing agent can be accelerated. Moreover, since the texturing particles can be reused, the use cost of the photovoltaic crystalline silicon texturing agent is effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a flow chart of a method for preparing a photovoltaic crystalline silicon texturing agent. DETAILED DESCRIPTION

[0020] A method for preparing a photovoltaic crystalline silicon texturing agent comprises the following steps:

[0021] Step 1: prepare alkaline solution, add xylitol and mannuronic acid into KOH solution in a ratio of (1-1.5):(1.5-2), heat and stir, then cool for later use;

[0022] Step 2: Preparation of velvet particles: fluorine-containing polymers, alkali-resistant organic polymers, and inorganic non-metallic particles are mixed in a specific ratio to obtain velvet particles for later use.

[0023] Step 3: Preparation of photovoltaic crystalline silicon texturing agent, adding the texturing particles prepared in step 2 to the alkaline solution prepared in step 1, and mixing and stirring at a temperature of 75-85°C to prepare the photovoltaic crystalline silicon texturing agent.

[0024] In this embodiment, the optimal ratio of xylitol to mannuronic acid in step 1 is 1.2:1.5, the heating temperature in step 1 is 60-80° C., and the reaction time is 3-8 hours.

[0025] In this embodiment, the texturing particles in step 2 are made of fluorine-containing polymer, alkali-resistant organic polymer, and inorganic non-metallic particles in a ratio of 1:1:0.5, and the particle size of the texturing particles is 100-400 μm.

[0026] In this embodiment, the fluorine polymer in step 2 is prepared by mixing polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, and tetrafluoroethylene-hexafluoropropylene copolymer in a ratio of 2:1:1.

[0027] In this embodiment, the alkali corrosion resistant organic polymer in step 2 is ultra-high molecular weight polyethylene, and the inorganic non-metallic particles in step 2 are nano-silicon dioxide particles.

[0028] In this embodiment, the method for the texturing particles to obtain kinetic energy in step 3 is to stir them.

[0029] In this embodiment, the method of using the photovoltaic crystalline silicon texturing agent is as follows: first, a layer of continuous microscopic V-shaped grooves with a depth of 3.2-3.5μm is opened on the surface of the photovoltaic crystalline silicon wafer to be texturized, and then the photovoltaic crystalline silicon wafer is added to the texturing agent and reacted at 70-90°C for 5-10 minutes. Then, the photovoltaic crystalline silicon wafer after the reaction is cleaned in a dark place to complete the texturing process on the surface of the photovoltaic crystalline silicon wafer.

[0030] In the present embodiment, the non-ionic surfactants xylitol and mannuronic acid in the alkali solution of the photovoltaic crystalline silicon texturing agent are outstanding representatives of sugar ether surfactants and are a new generation of green surfactants, which makes the photovoltaic crystalline silicon texturing agent less irritating to the human body when used and can be quickly biodegraded; at the same time, the texturing process of the texturing particles in the photovoltaic crystalline silicon texturing agent is mainly through the collision of the texturing particles with the hydrogen bubbles generated in the texturing process, so that the hydrogen bubbles are destroyed or split, and at the same time, the texturing particles desorb the hydrogen bubbles attached to the surface of the single crystal silicon wafer, thereby realizing the texturing of the surface of the single crystal silicon wafer.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a photovoltaic crystalline silicon texturing agent, characterized in that: It includes the following steps: Step 1: prepare alkaline solution, add xylitol and mannuronic acid into KOH solution in a ratio of (1-1.5):(1.5-2), heat and stir, then cool for later use; Step 2: Preparation of velvet particles: fluorine-containing polymers, alkali-resistant organic polymers, and inorganic non-metallic particles are mixed in a specific ratio to obtain velvet particles for later use. Step 3: Preparation of photovoltaic crystalline silicon texturing agent: adding the texturing particles prepared in step 2 to the alkaline solution prepared in step 1, and mixing and stirring at a temperature of 75-85° C. to obtain the photovoltaic crystalline silicon texturing agent.

2. The method for preparing a photovoltaic crystalline silicon texturing agent according to claim 1, characterized in that: The optimal ratio of xylitol to mannuronic acid in step 1 is 1.2:1.5, the heating temperature in step 1 is 60-80° C., and the reaction time is 3-8 hours.

3. The method for preparing a photovoltaic crystalline silicon texturing agent according to claim 1, characterized in that: The texturing particles in step 2 are made of fluorine-containing polymers, alkali-resistant organic polymers, and inorganic non-metallic particles in a ratio of 1:1:0.5, and the particle size of the texturing particles is 100-400 μm.

4. The method for preparing a photovoltaic crystalline silicon texturing agent according to claim 1, characterized in that: In the step 2, the fluorine polymer is prepared by mixing polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, and tetrafluoroethylene-hexafluoropropylene copolymer in a ratio of 2:1:

1.

5. The method for preparing a photovoltaic crystalline silicon texturing agent according to claim 1, characterized in that: The alkali corrosion resistant organic polymer in step 2 is ultra-high molecular weight polyethylene, and the inorganic non-metallic particles in step 2 are nano-silicon dioxide particles.

6. The method for preparing a photovoltaic crystalline silicon texturing agent according to claim 1, characterized in that: In step 3, the method for obtaining kinetic energy of the texturing particles is by stirring.

7. A method for preparing a photovoltaic crystalline silicon texturing agent according to any one of claims 1 to 6, characterized in that: The method of using the photovoltaic crystalline silicon texturing agent is as follows: first, a layer of continuous microscopic V-shaped grooves with a depth of 3.2-3.5μm is opened on the surface of the photovoltaic crystalline silicon wafer to be texturized, and then the photovoltaic crystalline silicon wafer is added to the texturing agent, and reacted at 70-90°C for 5-10 minutes. Then, the photovoltaic crystalline silicon wafer after the reaction is cleaned in a dark place to complete the texturing process on the surface of the photovoltaic crystalline silicon wafer.

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