Silicon wafer for solar cell, texturing method of silicon wafer, photoelectric device and photovoltaic system

Abstract

The invention provides a silicon wafer for a solar cell, a texturing method of the silicon wafer, a photoelectric device and a photovoltaic system, and relates to the technical field of crystalline silicon solar cells. The texturing method comprises the following steps: performing first texturing on a silicon wafer by using first texturing liquid to obtain a first target silicon wafer; performing secondary texturing on the first target silicon wafer by using a second texturing solution to form a pyramid-shaped textured structure with a curved surface structure on the side surface; the mass concentration of alkali in the first texturing liquid is higher than that of the second texturing liquid; the mass concentration of the first texturing additive in the first texturing liquid is higher than that of the second texturing liquid; the temperature of the first texturing is lower than that of the second texturing. According to the technical scheme, the interaction between the texturing liquid and the silicon wafer can be improved, the uniformity of the pyramid-shaped textured structure is improved, the lines of the pyramid-shaped textured structure are rounder, the curved pyramid-shaped textured structure is not prone to being broken, the effect of reducing the fragment rate of the silicon wafer is achieved, and then the long-term stability and reliability of the solar cell are improved.

Description

Technical Field

[0001] The present application relates to the technical field of crystalline silicon solar cells, and in particular to silicon wafers for solar cells and a texturing method thereof, optoelectronic devices and photovoltaic systems. Background Art

[0002] Silicon wafer texturing is a very important step in the manufacturing process of crystalline silicon solar cells. Its main purpose is to form a specific microstructure on the surface of the silicon wafer to improve the performance of the cell. Silicon wafers are usually textured using an alkaline pyramid etching method to form a random pyramid structure. The pyramid-shaped textured surface structure formed on the surface of the silicon wafer can reduce the reflection of sunlight, increase light absorption, and help improve the photoelectric conversion efficiency of the cell.

[0003] However, the traditional method of texturing silicon wafers to form a pyramid-shaped textured structure is easily broken when the silicon wafer is bent, and the fragmentation rate is high, which in turn affects the long-term stability and reliability of solar cells.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a silicon wafer for solar cells and a texturing method thereof, a photoelectric device and a photovoltaic system. The silicon wafer is sequentially texturized for the first time and the second time, and the process parameters of the first texturing and the second texturing are controlled, which can improve the interaction between the texturing liquid and the silicon wafer, improve the uniformity of the pyramid-shaped velvet structure, and modify the pyramid-shaped velvet structure to make the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side. When the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in reducing the fragmentation rate of the silicon wafer, thereby improving the long-term stability and reliability of the solar cell.

[0006] To achieve the above objectives, this application adopts the following technical solutions: A texturing method for silicon wafers for solar cells, comprising: Performing a first texturing on the silicon wafer using a first texturing liquid to obtain a first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive; The first target silicon wafer is subjected to a second texturing process using a second texturing liquid to form a pyramid-shaped texturing structure with a curved surface structure on the side, thereby obtaining the silicon wafer for solar cells; the second texturing liquid comprises a second alkali solution and a second texturing additive; Among them, the mass concentration of alkali in the first texturing liquid is higher than the mass concentration of alkali in the second texturing liquid; the mass concentration of the first texturing additive in the first texturing liquid is higher than the mass concentration of the second texturing additive in the second texturing liquid; the temperature of the first texturing is lower than the temperature of the second texturing.

[0007] In some embodiments, the mass concentration of the first texturing additive in the first texturing liquid is 0.5-1.5%; and / or The mass concentration of the second texturing additive in the second texturing liquid is 0.1-0.5%.

[0008] In some embodiments, the mass concentration of alkali in the first texturing solution is 0.5-5%; and / or The mass concentration of alkali in the second texturing solution is 0.2-1.5%.

[0009] In some embodiments, the sum of the time of the first texturing and the time of the second texturing is 400-500 seconds; Wherein, when the silicon wafer is subjected to the first texturing, the temperature is controlled at 70-85° C. and the time is controlled at 60-400 s; and / or When the first target silicon wafer is textured for the second time, the temperature is controlled at 85-90° C. and the time is controlled at 10-500 s.

[0010] In some embodiments, the first texturing additive includes isopropyl alcohol and an additive; the second texturing additive includes isopropyl alcohol and an additive; Wherein, the mass concentration of isopropanol in the first texturing additive is recorded as W1, and the mass concentration of the additive in the first texturing additive is recorded as W2; The mass concentration of isopropyl alcohol in the second texturing additive is recorded as W1', and the mass concentration of the additive in the second texturing additive is recorded as W2'; W1 and W1' satisfy: W1>W1'; W2 and W2' satisfy: W2<W2'.

[0011] In some embodiments, the texturing method further comprises: after the silicon wafer is subjected to the first texturing and before the first target silicon wafer is subjected to the second texturing, the first target silicon wafer is subjected to alkali washing; and / or After the first target silicon wafer is textured for the second time, the first target silicon wafer is alkaline washed.

[0012] The present application also provides a silicon wafer for solar cells, which is prepared by the above method.

[0013] The present application also provides a photoelectric device, comprising the above-mentioned silicon wafer for solar cells.

[0014] In some embodiments, the optoelectronic device comprises a crystalline silicon solar cell.

[0015] The present application also provides a photovoltaic system, comprising the above-mentioned photovoltaic device.

[0016] In the technical solution of the present application, the silicon wafer is subjected to the first and second texturing processes in sequence, and the process parameters of the first and second texturing processes are controlled, which can improve the interaction between the texturing liquid and the silicon wafer, improve the uniformity of the pyramid-shaped velvet structure, and modify the pyramid-shaped velvet structure to make the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side. When the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which reduces the fragmentation rate of the silicon wafer, thereby improving the long-term stability and reliability of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0018] Figure 1 Schematic diagram of the pyramid-shaped velvet structure prepared in Comparative Example 1 of the present application in its straight surface state and curved state.

[0019] Figure 2 Schematic diagram of the pyramid-shaped velvet structure prepared in the embodiment of the present application in the straight surface state and the curved state. DETAILED DESCRIPTION

[0020] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. Wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0021] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. When the second element, component, region, layer or part is discussed, it does not indicate that the present application necessarily has the first element, component, region, layer or part.

[0022] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0025] The embodiment of the present application aims to provide a silicon wafer for solar cells and a texturing method thereof, a photoelectric device and a photovoltaic system. In the technical solution of the present application, the silicon wafer is sequentially texturized for the first time and the second time, and the process parameters of the first and the second texturing are controlled, which can improve the interaction between the texturing liquid and the silicon wafer, improve the uniformity of the pyramid-shaped velvet structure, and modify the pyramid-shaped velvet structure to make the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side. When the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in reducing the silicon wafer fragmentation rate, thereby improving the long-term stability and reliability of the solar cell. In addition, the curved pyramid-shaped velvet structure can further reduce light loss, thereby improving the light absorption effect. And the functional layers such as the PN junction, the passivation layer, and the anti-reflection film are more easily and evenly laid on the surface of the curved pyramid-shaped velvet structure, and the connection tightness of each functional layer and the curved pyramid-shaped velvet structure is higher, thereby effectively improving the photoelectric conversion efficiency of the battery.

[0026] The present application provides a texturing method for a silicon wafer for a solar cell, comprising: Performing a first texturing on the silicon wafer using a first texturing liquid to obtain a first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive; The first target silicon wafer is subjected to a second texturing process using a second texturing liquid to form a pyramid-shaped texturing structure with a curved surface structure on the side, thereby obtaining the silicon wafer for solar cells; the second texturing liquid comprises a second alkali solution and a second texturing additive; Among them, the mass concentration of alkali in the first texturing liquid is higher than the mass concentration of alkali in the second texturing liquid; the mass concentration of the first texturing additive in the first texturing liquid is higher than the mass concentration of the second texturing additive in the second texturing liquid; the temperature of the first texturing is lower than the temperature of the second texturing.

[0027] In the embodiment of the present application, the type of silicon wafer for solar cells can be monocrystalline silicon or polycrystalline silicon. The texturing method of silicon wafer for solar cells can be used for single-sided texturing or double-sided texturing. Single-sided texturing or double-sided texturing can be selected according to actual needs. In the embodiment of the present application, the first alkali solution can be a sodium hydroxide solution or a potassium hydroxide solution, and the second alkali solution can be a sodium hydroxide solution or a potassium hydroxide solution. The first alkali solution and the second alkali solution can be the same or different. In addition, the first texturing additive and the second texturing additive can be the same or different.

[0028] In the embodiment of the present application, the silicon wafer is subjected to the first and second texturing in sequence, and the process parameters of the first and second texturing are controlled, which can improve the interaction between the texturing liquid and the silicon wafer, improve the uniformity of the pyramid-shaped velvet structure, and modify the pyramid-shaped velvet structure to make the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side. When the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in reducing the silicon wafer fragmentation rate, thereby improving the long-term stability and reliability of the solar cell. In addition, the curved pyramid-shaped velvet structure can further reduce light loss, thereby improving the light absorption effect. And the connection tightness between each functional layer and the curved pyramid-shaped velvet structure is higher, thereby effectively improving the photoelectric conversion efficiency of the battery.

[0029] In an optional embodiment, the mass concentration of the first texturing additive in the first texturing liquid is 0.5-1.5% (for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%); and / or The mass concentration of the second texturing additive in the second texturing liquid is 0.1-0.5% (for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%).

[0030] In the embodiments of the present application, the concentration of the texturing additive in the texturing liquid is optimized, which can improve the interaction between the texturing liquid and the silicon wafer, so that a higher reaction rate difference is formed between the top and bottom of the tower, which helps to modify the pyramid-shaped velvet structure, making the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side, and when the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which further reduces the silicon wafer fragmentation rate, thereby further improving the long-term stability and reliability of the solar cell. In addition, the curved pyramid-shaped velvet structure can further reduce light loss, thereby improving the light absorption effect.

[0031] In an optional embodiment, the mass concentration of alkali in the first texturing solution is 0.5-5% (for example, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%); and / or The mass concentration of alkali in the second texturing solution is 0.2-1.5% (for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%).

[0032] In the embodiment of the present application, the concentration of alkali in the texturing solution is optimized, which can improve the interaction between the texturing solution and the silicon wafer, so that a higher reaction rate difference is formed between the top and bottom of the tower, which helps to modify the pyramid-shaped velvet structure, making the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side, and when the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which further reduces the silicon wafer fragmentation rate, thereby further improving the long-term stability and reliability of the solar cell. In addition, the curved pyramid-shaped velvet structure can further reduce light loss, thereby improving the light absorption effect.

[0033] In an optional embodiment, the sum of the time of the first texturing and the time of the second texturing is 400-500s (for example, 400s, 410s, 420s, 430s, 440s, 450s, 460s, 470s, 480s, 490s, 500s); Wherein, when the silicon wafer is textured for the first time, the temperature is controlled at 70-85°C (for example, 70°C, 72°C, 74°C, 76°C, 78°C, 80°C, 82°C, 84°C, 85°C), and the time is controlled at 60-400s (for example, 60s, 100s, 150s, 200s, 250s, 300s, 350s, 400s); and / or When the first target silicon wafer is textured for the second time, the temperature is controlled at 85~90℃ (for example, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃), and the time is controlled at 10~500s (for example, 10s, 50s, 100s, 150s, 200s, 250s, 300s, 350s, 400s, 450s, 500s).

[0034] In the embodiment of the present application, the temperature of texturing is optimized, which can improve the interaction between the texturing liquid and the silicon wafer, so that a higher reaction rate difference is formed between the top and bottom of the tower, which is helpful to modify the pyramid-shaped velvet structure, make the lines of the pyramid-shaped velvet structure more rounded, and form a pyramid-shaped velvet structure with a curved surface structure on the side. When the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which further reduces the silicon wafer fragmentation rate, thereby further improving the long-term stability and reliability of the solar cell. It can also further reduce light loss, thereby improving the light absorption effect.

[0035] In an optional embodiment, the first texturing additive includes isopropyl alcohol and an additive; the second texturing additive includes isopropyl alcohol and an additive; Wherein, the mass concentration of isopropanol in the first texturing additive is recorded as W1, and the mass concentration of the additive in the first texturing additive is recorded as W2; The mass concentration of isopropyl alcohol in the second texturing additive is recorded as W1', and the mass concentration of the additive in the second texturing additive is recorded as W2'; W1 and W1' satisfy: W1>W1'; W2 and W2' satisfy: W2<W2'.

[0036] It should be noted that the classic formula of texturing additives is: texturing additives, calculated by mass percentage, include: sodium hydroxide 0.1%~3%, isopropyl alcohol 2%~10%, additives 0.01%~2%, and the balance is water, totaling 100%; among them, additives, calculated by mass percentage, include: glucose, sodium gluconate or potassium gluconate 0.001%~3%, polyoxyethylene ether 100ppb~8000ppb, sodium lactate or sodium citrate 0.001%~2%, propylene glycol 0.001%~2%, sodium silicate 0.01%~6%, sodium carbonate or sodium bicarbonate 0.001%~2%, and the balance is water, totaling 100%. In the embodiment of the present application, the content of isopropanol and additives in the velvet additive is optimized, which can improve the interaction between the velvet liquid and the silicon wafer, so that the top and bottom of the tower form a higher reaction rate difference, which helps to modify the pyramid-shaped velvet structure, making the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side, and when the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in further reducing the silicon wafer fragmentation rate, thereby further improving the long-term stability and reliability of the solar cell. It can also further reduce light loss, thereby improving the light absorption effect.

[0037] In an optional embodiment, the texturing method further comprises: after the silicon wafer is texturized for the first time and before the first target silicon wafer is texturized for the second time, alkali washing the first target silicon wafer; and / or After the first target silicon wafer is textured for the second time, the first target silicon wafer is alkaline washed.

[0038] In the embodiment of the present application, alkaline washing is performed on the silicon wafer to effectively remove impurities on the surface of the silicon wafer and improve the cleanliness of the prepared silicon wafer.

[0039] The following specific examples further illustrate the present application, but should not be construed as limiting the present application. Without departing from the spirit and substance of the present application, modifications or replacements made to the methods, steps or conditions of the present application are within the scope of the present application.

[0040] Example 1 A texturing method for silicon wafers for solar cells, comprising: (1) Pre-cleaning: Place a 150 μm thick single crystal silicon wafer in a mixture of NaOH + H2O2 for pre-cleaning, and roughly polish to remove the damaged layer and impurities on the surface of the silicon wafer to obtain a pre-cleaned silicon wafer; (2) First water washing: clean the pre-cleaned silicon wafer with pure water to obtain a single-washed silicon wafer; (3) First texturing: The first texturing liquid is used to perform the first texturing on the washed silicon wafer. During the first texturing, the temperature is controlled at 70°C and the time is controlled at 60 seconds to obtain the first target silicon wafer. The first texturing liquid includes a first alkali solution and a first texturing additive. The mass concentration of the first texturing additive in the first texturing liquid is 0.5%. The first alkali solution is a sodium hydroxide solution. The mass concentration of sodium hydroxide in the first texturing liquid is 0.5%. The model of the first texturing additive is Shichuang TS50. (4) First alkaline washing: The first target silicon wafer is placed in a mixture of NaOH and H2O2 for alkaline washing to remove impurities on the surface of the silicon wafer, thereby obtaining a silicon wafer that has been washed once; (5) Second texturing: The silicon wafer that has been alkali-washed once is texturized for the second time using a second texturing liquid. During the second texturing, the temperature is controlled at 85°C and the time is controlled at 440s to obtain a silicon wafer that has been texturized for the second time. The second texturing liquid includes a second alkali liquid and a second texturing additive. The mass concentration of the second texturing additive in the second texturing liquid is 0.1%. The second alkali liquid is a sodium hydroxide solution. The mass concentration of sodium hydroxide in the second texturing liquid is 0.2%. The model of the second texturing additive is Shichuang TS50. (6) Second alkaline washing: The silicon wafer after the second texturing is placed in a mixture of NaOH + H2O2 for alkaline washing to remove impurities on the surface of the silicon wafer, thereby obtaining a silicon wafer after the second alkaline washing; (7) Second water washing: Use pure water to clean the alkali solution on the surface of the silicon wafer after the second alkali washing to obtain a second water-washed silicon wafer; (8) Pickling: Pickling the silicon wafer after the second water washing with hydrofluoric acid to remove metal impurities and make the silicon wafer easier to dehydrate, thereby obtaining an acid-washed silicon wafer; (9) Third water washing: Use pure water to clean the hydrofluoric acid on the surface of the acid-washed silicon wafer to obtain a three-washed silicon wafer; (10) Drying: Drying the washed silicon wafer three times to obtain the silicon wafer for solar cells; the pyramid-shaped velvet structure of the silicon wafer for solar cells in the straight state and the curved state is as follows: Figure 2 shown.

[0041] Example 2 A texturing method for silicon wafers for solar cells, comprising: (1) Pre-cleaning: Place a 150 μm thick single crystal silicon wafer in a mixture of NaOH + H2O2 for pre-cleaning, and roughly polish to remove the damaged layer and impurities on the surface of the silicon wafer to obtain a pre-cleaned silicon wafer; (2) First water washing: clean the pre-cleaned silicon wafer with pure water to obtain a single-washed silicon wafer; (3) First texturing: The first texturing liquid is used to perform the first texturing on the washed silicon wafer. During the first texturing, the temperature is controlled at 85°C and the time is controlled at 400 seconds to obtain the first target silicon wafer. The first texturing liquid includes a first alkali liquid and a first texturing additive. The mass concentration of the first texturing additive in the first texturing liquid is 1.5%. The first alkali liquid is a potassium hydroxide solution. The mass concentration of potassium hydroxide in the first texturing liquid is 5%. The model of the first texturing additive is Shichuang TS52. (4) First alkaline washing: The first target silicon wafer is placed in a mixture of NaOH and H2O2 for alkaline washing to remove impurities on the surface of the silicon wafer, thereby obtaining a silicon wafer that has been washed once; (5) Second texturing: The silicon wafer that has been alkali-washed once is texturized for the second time using a second texturing liquid. During the second texturing, the temperature is controlled at 90°C and the time is controlled at 50 seconds to obtain a silicon wafer that has been texturized for the second time. The second texturing liquid includes a second alkali liquid and a second texturing additive. The mass concentration of the second texturing additive in the second texturing liquid is 0.5%. The second alkali liquid is a potassium hydroxide solution. The mass concentration of potassium hydroxide in the second texturing liquid is 1.5%. The model of the second texturing additive is Shichuang TS52. (6) Second alkaline washing: The silicon wafer after the second texturing is placed in a mixture of NaOH + H2O2 for alkaline washing to remove impurities on the surface of the silicon wafer, thereby obtaining a silicon wafer after the second alkaline washing; (7) Second water washing: Use pure water to clean the alkali solution on the surface of the silicon wafer after the second alkali washing to obtain a second water-washed silicon wafer; (8) Pickling: Pickling the silicon wafer after the second water washing with hydrofluoric acid to remove metal impurities and make the silicon wafer easier to dehydrate, thereby obtaining an acid-washed silicon wafer; (9) Third water washing: Use pure water to clean the hydrofluoric acid on the surface of the acid-washed silicon wafer to obtain a three-washed silicon wafer; (10) Drying: Drying the washed silicon wafer three times to obtain the silicon wafer for solar cells; the pyramid-shaped velvet structure of the silicon wafer for solar cells in the straight state and the curved state is as follows: Figure 2 shown.

[0042] Example 3 A texturing method for silicon wafers for solar cells, comprising: (1) Pre-cleaning: Place a 150 μm thick single crystal silicon wafer in a mixture of NaOH + H2O2 for pre-cleaning, and roughly polish to remove the damaged layer and impurities on the surface of the silicon wafer to obtain a pre-cleaned silicon wafer; (2) First water washing: clean the pre-cleaned silicon wafer with pure water to obtain a single-washed silicon wafer; (3) First texturing: The first texturing liquid is used to perform the first texturing on the washed silicon wafer. During the first texturing, the temperature is controlled at 75°C and the time is controlled at 200 seconds to obtain the first target silicon wafer. The first texturing liquid includes a first alkali solution and a first texturing additive. The mass concentration of the first texturing additive in the first texturing liquid is 0.8%. The first alkali solution is a sodium hydroxide solution. The mass concentration of sodium hydroxide in the first texturing liquid is 2%. The model of the first texturing additive is Shichuang TS50. (4) First alkaline washing: The first target silicon wafer is placed in a mixture of NaOH and H2O2 for alkaline washing to remove impurities on the surface of the silicon wafer, thereby obtaining a silicon wafer that has been washed once; (5) Second texturing: The silicon wafer that has been alkali-washed once is texturized for the second time using a second texturing liquid. During the second texturing, the temperature is controlled at 87°C and the time is controlled at 200 seconds to obtain a silicon wafer that has been texturized for the second time. The second texturing liquid includes a second alkali liquid and a second texturing additive. The mass concentration of the second texturing additive in the second texturing liquid is 0.3%. The second alkali liquid is a potassium hydroxide solution. The mass concentration of potassium hydroxide in the second texturing liquid is 0.7%. The model of the second texturing additive is Shichuang TS52. (6) Second alkaline washing: The silicon wafer after the second texturing is placed in a mixture of NaOH + H2O2 for alkaline washing to remove impurities on the surface of the silicon wafer, thereby obtaining a silicon wafer after the second alkaline washing; (7) Second water washing: Use pure water to clean the alkali solution on the surface of the silicon wafer after the second alkali washing to obtain a second water-washed silicon wafer; (8) Pickling: Pickling the silicon wafer after the second water washing with hydrofluoric acid to remove metal impurities and make the silicon wafer easier to dehydrate, thereby obtaining an acid-washed silicon wafer; (9) Third water washing: Use pure water to clean the hydrofluoric acid on the surface of the acid-washed silicon wafer to obtain a three-washed silicon wafer; (10) Drying: Drying the washed silicon wafer three times to obtain the silicon wafer for solar cells; the pyramid-shaped velvet structure of the silicon wafer for solar cells in the straight state and the curved state is as follows: Figure 2 shown.

[0043] Example 4 The silicon wafer for solar cell of Example 4 is prepared by referring to the texturing method of Example 3, except that: Step (3) in Example 4 is: using the first texturing liquid to perform the first texturing on the washed silicon wafer, during the first texturing, the temperature is controlled at 75°C, the time is controlled at 200s, to obtain the first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing liquid is 0.3%; the first alkali solution is a sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing liquid is 2%; the model of the first texturing additive is Shichuang TS50.

[0044] Step (5) in Example 4 is: using a second texturing liquid to texturize the silicon wafer that has been alkali-washed once for a second time, during the second texturizing, the temperature is controlled at 87°C, the time is controlled at 200s, to obtain a second texturized silicon wafer; the second texturizing liquid includes a second alkali liquid and a second texturizing additive, the mass concentration of the second texturizing additive in the second texturizing liquid is 0.1%; the second alkali liquid is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturizing liquid is 0.7%; the model of the second texturizing additive is Shichuang TS52.

[0045] Example 5 The silicon wafer for solar cell of Example 5 is prepared by referring to the texturing method of Example 3, except that: Step (3) in Example 5 is: using the first texturing liquid to perform the first texturing on the washed silicon wafer, during the first texturing, the temperature is controlled at 75°C, the time is controlled at 200s, to obtain the first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing liquid is 1.5%; the first alkali solution is a sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing liquid is 2%; the model of the first texturing additive is Shichuang TS50.

[0046] Step (5) in Example 5 is: using a second texturing liquid to texturize the silicon wafer that has been alkali-washed once for a second time, during the second texturing, the temperature is controlled at 87°C, the time is controlled at 200s, to obtain a second texturized silicon wafer; the second texturing liquid includes a second alkali liquid and a second texturing additive, the mass concentration of the second texturing additive in the second texturing liquid is 0.9%; the second alkali liquid is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing liquid is 0.7%; the model of the second texturing additive is Shichuang TS52.

[0047] Example 6 The silicon wafer for solar cell of Example 6 is prepared by referring to the texturing method of Example 3, except that: Step (3) in Example 6 is: using the first texturing liquid to perform the first texturing on the washed silicon wafer, during the first texturing, the temperature is controlled at 75°C, the time is controlled at 200s, to obtain the first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing liquid is 0.8%; the first alkali solution is a sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing liquid is 5%; the model of the first texturing additive is Shichuang TS50.

[0048] Step (5) in Example 6 is: using a second texturing liquid to texturize the silicon wafer that has been alkali-washed once for a second time, during the second texturing, the temperature is controlled at 87°C, the time is controlled at 200s, to obtain a second texturized silicon wafer; the second texturing liquid includes a second alkali liquid and a second texturing additive, the mass concentration of the second texturing additive in the second texturing liquid is 0.3%; the second alkali liquid is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing liquid is 3%; the model of the second texturing additive is Shichuang TS52.

[0049] Example 7 The silicon wafer for solar cell of Example 7 was prepared by referring to the texturing method of Example 3, except that: Step (3) in Example 7 is: using the first texturing liquid to perform the first texturing on the washed silicon wafer, during the first texturing, the temperature is controlled at 75°C, the time is controlled at 200s, to obtain the first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing liquid is 0.8%; the first alkali solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the first texturing liquid is 0.3%; the model of the first texturing additive is Shichuang TS50.

[0050] Step (5) in Example 7 is: using a second texturing liquid to texturize the silicon wafer that has been alkali-washed once for a second time, during the second texturizing, the temperature is controlled at 87°C, the time is controlled at 200s, to obtain a second texturized silicon wafer; the second texturizing liquid includes a second alkali liquid and a second texturizing additive, the mass concentration of the second texturizing additive in the second texturizing liquid is 0.3%; the second alkali liquid is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturizing liquid is 2%; the model of the second texturizing additive is Shichuang TS52.

[0051] Example 8 The silicon wafer for solar cell of Example 8 was prepared by referring to the texturing method of Example 3, except that: Step (3) in Example 8 is: using the first texturing liquid to perform the first texturing on the washed silicon wafer, during the first texturing, the temperature is controlled at 70°C, the time is controlled at 200s, to obtain the first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing liquid is 0.8%; the first alkali solution is a sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing liquid is 2%; the model of the first texturing additive is Shichuang TS50.

[0052] Step (5) in Example 8 is: using a second texturing liquid to texturize the silicon wafer that has been alkali-washed once for a second time, during the second texturizing, the temperature is controlled at 75°C, the time is controlled at 200s, to obtain a second texturized silicon wafer; the second texturizing liquid includes a second alkali liquid and a second texturizing additive, the mass concentration of the second texturizing additive in the second texturizing liquid is 0.3%; the second alkali liquid is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturizing liquid is 0.7%; the model of the second texturizing additive is Shichuang TS52.

[0053] Example 9 The silicon wafer for solar cell of Example 9 was prepared by referring to the texturing method of Example 3, except that: Step (3) in Example 9 is: using the first texturing liquid to perform the first texturing on the washed silicon wafer, during the first texturing, the temperature is controlled at 75°C, the time is controlled at 200s, to obtain the first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing liquid is 0.8%; the first alkali solution is a sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing liquid is 2%; the model of the first texturing additive is Shichuang TS50.

[0054] Step (5) in Example 9 is: using a second texturing liquid to texturize the silicon wafer that has been alkali-washed once for a second time, during the second texturing, the temperature is controlled at 80°C, the time is controlled at 200s, to obtain a second texturized silicon wafer; the second texturing liquid includes a second alkali liquid and a second texturing additive, the mass concentration of the second texturing additive in the second texturing liquid is 0.3%; the second alkali liquid is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing liquid is 0.7%; the model of the second texturing additive is Shichuang TS52.

[0055] Example 10 The silicon wafer for solar cell of Example 10 was prepared by referring to the texturing method of Example 3, except that: Step (3) in Example 10 is: using a first texturing liquid to perform a first texturing on a silicon wafer that has been washed once, during the first texturing, the temperature is controlled at 75°C, the time is controlled at 200s, and a first target silicon wafer is obtained; the first texturing liquid includes a first alkali solution and a first texturing additive, and the mass concentration of the first texturing additive in the first texturing liquid is 0.8%; the first alkali solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the first texturing liquid is 2%; the first texturing additive, calculated by mass percentage, includes: 0.5% sodium hydroxide, 5% isopropanol, 0.5% additive, and the balance is water, totaling 100%; the additive, calculated by mass percentage, includes: 0.06% sodium gluconate, 3000ppb polyoxyethylene ether, 0.2% sodium citrate, 0.7% propylene glycol, 0.9% sodium silicate, 0.6% sodium carbonate, and the balance is water, totaling 100%.

[0056] Step (5) in Example 10 is: using a second texturing liquid to perform a second texturing on the silicon wafer that has been alkali-washed once, during the second texturing, the temperature is controlled at 87°C, the time is controlled at 200s, and a silicon wafer that has been texturized twice is obtained; the second texturing liquid includes a second alkali liquid and a second texturing additive, and the mass concentration of the second texturing additive in the second texturing liquid is 0.3%; the second alkali liquid is a potassium hydroxide solution, and the mass concentration of potassium hydroxide in the second texturing liquid is 0.7%; the second texturing additive, calculated by mass percentage, includes: 0.5% sodium hydroxide, 3% isopropanol, 0.7% additive, and the balance is water, totaling 100%; the additive, calculated by mass percentage, includes: 0.06% sodium gluconate, 3000 ppb polyoxyethylene ether, 0.2% sodium citrate, 0.7% propylene glycol, 0.9% sodium silicate, 0.6% sodium carbonate, and the balance is water, totaling 100%.

[0057] Embodiment 11 The silicon wafer for solar cell of Example 11 was prepared by referring to the texturing method of Example 3, except that: Step (3) in Example 11 is: using a first texturing liquid to perform a first texturing on a silicon wafer that has been washed once, and during the first texturing, the temperature is controlled at 75°C and the time is controlled at 200s to obtain a first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive, and the mass concentration of the first texturing additive in the first texturing liquid is 0.8%; the first alkali solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the first texturing liquid is 2%; the first texturing additive, calculated by mass percentage, includes: 0.5% sodium hydroxide, 7% isopropanol, 0.5% additive, and the balance is water, totaling 100%; the additive, calculated by mass percentage, includes: 0.06% sodium gluconate, 3000 ppb polyoxyethylene ether, 0.2% sodium citrate, 0.7% propylene glycol, 0.9% sodium silicate, 0.6% sodium carbonate, and the balance is water, totaling 100%.

[0058] Step (5) in Example 11 is: using a second texturing liquid to texturize the silicon wafer that has been alkali-washed once for a second time, during the second texturizing, the temperature is controlled at 87°C, the time is controlled at 200s, and a silicon wafer that has been texturized twice is obtained; the second texturizing liquid includes a second alkali liquid and a second texturizing additive, and the mass concentration of the second texturizing additive in the second texturizing liquid is 0.3%; the second alkali liquid is a potassium hydroxide solution, and the mass concentration of potassium hydroxide in the second texturizing liquid is 0.7%; the second texturizing additive, calculated by mass percentage, includes: 0.5% sodium hydroxide, 2% isopropanol, 2% additive, and the balance is water, totaling 100%; the additive, calculated by mass percentage, includes: 0.06% sodium gluconate, 3000 ppb polyoxyethylene ether, 0.2% sodium citrate, 0.7% propylene glycol, 0.9% sodium silicate, 0.6% sodium carbonate, and the balance is water, totaling 100%.

[0059] Comparative Example 1 A texturing method for silicon wafers for solar cells, comprising: (1) Pre-cleaning: Place a 150 μm thick single crystal silicon wafer in a mixture of NaOH + H2O2 for pre-cleaning, and roughly polish to remove the damaged layer and impurities on the surface of the silicon wafer to obtain a pre-cleaned silicon wafer; (2) First water washing: clean the pre-cleaned silicon wafer with pure water to obtain a single-washed silicon wafer; (3) Texturing: The silicon wafer washed once is subjected to the first texturing using a texturing liquid. During the first texturing, the temperature is controlled at 80°C and the time is controlled at 400 seconds to obtain the first target silicon wafer. The texturing liquid includes an alkali solution and a texturing additive. The mass concentration of the texturing additive in the texturing liquid is 0.8%. The alkali solution is a sodium hydroxide solution. The mass concentration of the sodium hydroxide in the first texturing liquid is 1.5%. The model of the texturing additive is Shichuang TS50. (4) Alkaline washing: placing the first target silicon wafer in a mixture of NaOH+H2O2 for alkaline washing to remove impurities on the surface of the silicon wafer, thereby obtaining an alkaline-washed silicon wafer; (5) Second water washing: Use pure water to clean the alkali solution on the surface of the alkali-washed silicon wafer to obtain a second-washed silicon wafer; (6) Pickling: Pickling the silicon wafer after the second water washing with hydrochloric acid + hydrofluoric acid to remove impurities on the surface of the silicon wafer to obtain an acid-washed silicon wafer; (7) Third water washing: Use pure water to clean the acid on the surface of the acid-washed silicon wafer to obtain a three-washed silicon wafer; (8) Slow pulling: The silicon wafer washed three times is slowly pulled with pure water to remove the acid solution and pre-dehydrate the silicon wafer to obtain a slow-pulled silicon wafer; (9) Drying: Drying the washed silicon wafer three times in a nitrogen atmosphere to obtain the silicon wafer for solar cells; the pyramid-shaped velvet structure of the silicon wafer for solar cells in the straight state and the curved state is as follows: Figure 1 shown.

[0060] The silicon wafers for solar cells prepared in the above embodiments and comparative examples were tested, and the test results are shown in Table 1 below.

[0061] Table 1 (Data on the effect of reducing the silicon wafer fragmentation rate and the effect of reducing the silicon wafer reflectivity of Examples 1-11 are obtained by taking Comparative Example 1 as a reference)

[0062] The data in the above table show that, taking Example 1 as an example, the silicon wafer fragmentation rate in Example 1 is reduced by 0.55% compared with that in Comparative Example 1; the silicon wafer reflectivity in Example 1 is reduced by 0.21% compared with that in Comparative Example 1. Referring to the detection data of the above Examples 1-11, it can be seen that in the technical solution of the present application, the silicon wafer is subjected to the first and second texturing in sequence, and the process parameters of the first and second texturing are controlled, which can improve the interaction between the texturing liquid and the silicon wafer, improve the uniformity of the pyramid-shaped velvet structure, and modify the pyramid-shaped velvet structure to make the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side. When the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in reducing the silicon wafer fragmentation rate, thereby improving the long-term stability and reliability of the solar cell. It can also further reduce light loss, thereby improving the light absorption effect.

[0063] Referring to the test data of the above-mentioned Examples 1-3 and Examples 4-5, it can be known that optimizing the concentration of the texturing additive in the texturing liquid can improve the interaction between the texturing liquid and the silicon wafer, so that a higher reaction rate difference is formed between the top and bottom of the tower, which is helpful to modify the pyramid-shaped velvet structure, making the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side, and when the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which further reduces the fragmentation rate of the silicon wafer, thereby further improving the long-term stability and reliability of the solar cell. It can also further reduce light loss, thereby improving the light absorption effect.

[0064] Referring to the test data of the above-mentioned embodiment 3, embodiment 6-7, it can be known that optimizing the concentration of alkali in the texturing liquid can improve the interaction between the texturing liquid and the silicon wafer, so that a higher reaction rate difference is formed between the top and bottom of the tower, which is helpful to modify the pyramid-shaped velvet structure, making the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side, and when the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in further reducing the fragmentation rate of the silicon wafer, thereby further improving the long-term stability and reliability of the solar cell. It can also further reduce light loss, thereby improving the light absorption effect. .

[0065] Referring to the test data of the above-mentioned embodiment 3, embodiment 8-9, it can be known that optimizing the temperature of texturing can improve the interaction between the texturing liquid and the silicon wafer, so that a higher reaction rate difference is formed between the top and bottom of the tower, which is helpful to modify the pyramid-shaped velvet structure, making the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side, and when the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in further reducing the fragmentation rate of the silicon wafer, thereby further improving the long-term stability and reliability of the solar cell. It can also further reduce light loss, thereby improving the light absorption effect.

[0066] Referring to the test data of the above-mentioned embodiment 3 and embodiments 10-11, it can be known that optimizing the content of isopropyl alcohol and additives in the velvet additive can improve the interaction between the velvet liquid and the silicon wafer, so that a higher reaction rate difference is formed between the top and bottom of the tower, which is helpful to modify the pyramid-shaped velvet structure, making the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side, and when the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in further reducing the fragmentation rate of the silicon wafer, thereby further improving the long-term stability and reliability of the solar cell. It can also further reduce light loss, thereby improving the light absorption effect.

[0067] In summary, in the technical solution of the present application, the silicon wafer is subjected to the first and second texturing processes in sequence, and the process parameters of the first and second texturing processes are controlled, which can improve the interaction between the texturing liquid and the silicon wafer, improve the uniformity of the pyramid-shaped velvet structure, and modify the pyramid-shaped velvet structure to make the lines of the pyramid-shaped velvet structure more rounded, forming a pyramid-shaped velvet structure with a curved surface structure on the side. When the silicon wafer is bent, the curved pyramid-shaped velvet structure is not easy to break, which plays a role in reducing the fragmentation rate of the silicon wafer, thereby improving the long-term stability and reliability of the solar cell. It can also further reduce light loss, thereby improving the light absorption effect.

[0068] In addition, when the silicon wafer is textured according to the method in comparative example 1, in order to ensure the quality of the silicon wafer, the drying must be carried out in a nitrogen atmosphere, which will increase the drying cost of the silicon wafer; when the silicon wafer is textured according to the method in the embodiment of the present application, the final drying step can be carried out in an air atmosphere, which is relatively cheaper. It can be seen that referring to the texture making process of the present application is beneficial to the subsequent drying step.

[0069] The present application can provide a silicon wafer for solar cells, which is prepared by the above method. The silicon wafer for solar cells also has the advantages possessed by the silicon wafer for solar cells prepared by the above method.

[0070] The present application may provide a photoelectric device, including the above-mentioned silicon wafer for solar cells. The above-mentioned advantages of the silicon wafer for solar cells are also possessed by the silicon wafer for solar cells. The photoelectric device includes a crystalline silicon solar cell.

[0071] The present application may provide a photovoltaic system, including the above-mentioned optoelectronic device (such as a crystalline silicon solar cell). The advantages of the above-mentioned solar cell are also possessed by the photovoltaic system, which will not be repeated here. The above-mentioned photovoltaic system has a wide range of applications, not only limited to photovoltaic power stations, such as ground power stations, rooftop power stations and water power stations, but also includes various equipment and devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars and solar buildings. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be used in all fields where solar energy is required for power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components may form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid, and then connected to the mains network to realize solar power supply.

[0072] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application 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 cannot be understood as a limitation on the present application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0073] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0074] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0075] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for texturing a silicon wafer for a solar cell, characterized in that: include: Performing a first texturing on the silicon wafer using a first texturing liquid to obtain a first target silicon wafer; the first texturing liquid includes a first alkali solution and a first texturing additive; The first target silicon wafer is subjected to a second texturing process using a second texturing liquid to form a pyramid-shaped texturing structure with a curved surface structure on the side, thereby obtaining the silicon wafer for solar cells; the second texturing liquid comprises a second alkali solution and a second texturing additive; Among them, the mass concentration of alkali in the first texturing liquid is higher than the mass concentration of alkali in the second texturing liquid; the mass concentration of the first texturing additive in the first texturing liquid is higher than the mass concentration of the second texturing additive in the second texturing liquid; the temperature of the first texturing is lower than the temperature of the second texturing.

2. The method according to claim 1, characterized in that The mass concentration of the first texturing additive in the first texturing liquid is 0.5-1.5%; and / or The mass concentration of the second texturing additive in the second texturing liquid is 0.1-0.5%.

3. The method according to claim 1, characterized in that The mass concentration of alkali in the first texturing solution is 0.5-5%; and / or The mass concentration of alkali in the second texturing solution is 0.2-1.5%.

4. The method according to claim 1, characterized in that: The sum of the time of the first texturing and the time of the second texturing is 400-500s; Wherein, when the silicon wafer is subjected to the first texturing, the temperature is controlled at 70-85° C. and the time is controlled at 60-400 s; and / or When the first target silicon wafer is textured for the second time, the temperature is controlled at 85-90° C. and the time is controlled at 10-500 s.

5. The method according to claim 1, characterized in that: The first texturing additive includes isopropyl alcohol and an additive; the second texturing additive includes isopropyl alcohol and an additive; Wherein, the mass concentration of isopropanol in the first texturing additive is recorded as W1, and the mass concentration of the additive in the first texturing additive is recorded as W2; The mass concentration of isopropyl alcohol in the second texturing additive is recorded as W1', and the mass concentration of the additive in the second texturing additive is recorded as W2'; W1 and W1' satisfy: W1>W1'; W2 and W2' satisfy: W2<W2'.

6. The method according to claim 1, characterized in that Also includes: After the silicon wafer is subjected to the first texturing, and before the first target silicon wafer is subjected to the second texturing, the first target silicon wafer is subjected to alkali washing; and / or After the first target silicon wafer is textured for the second time, the first target silicon wafer is alkaline washed.

7. A silicon wafer for solar cells, characterized in that: The method is prepared by the method according to any one of claims 1 to 6.

8. A photoelectric device, characterized in that: Comprising the silicon wafer for solar cells as claimed in claim 7.

9. The optoelectronic device according to claim 8, characterized in that: The optoelectronic device includes a crystalline silicon solar cell.

10. A photovoltaic system, characterized in that: Comprising the optoelectronic device according to claim 8 or 9.

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