Crystalline silicon textured structure, battery, preparation method of crystalline silicon textured structure and battery, and photovoltaic module

Abstract

The invention relates to a crystalline silicon textured structure, a battery, a preparation method of the crystalline silicon textured structure and a photovoltaic module. The crystalline silicon textured structure comprises a silicon substrate and a pyramid-like structure arranged on the silicon substrate, the pyramid-like structure comprises a first part and a second part, the first part is located on the side, away from the silicon substrate, of the second part, the first part is provided with a first side face, the first side face is of a concave structure, and the first part is of a spine structure. In the crystalline silicon textured structure, the first part is provided with the first side surface with the concave structure, and the first part is of the spine structure, so that a contact point position for easily transmitting current can be provided, the filling factor of the battery is improved, and the photoelectric conversion efficiency of the battery is further improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a crystalline silicon textured structure, a battery and a preparation method thereof, and a photovoltaic module. Background Art

[0002] Solar energy, due to its advantages of being clean, safe, and abundant, has become a rapidly growing renewable energy source, with photovoltaic power generation being one of its key uses. Crystalline silicon cells, with their mature manufacturing processes and stable performance, dominate the photovoltaic market. However, the photoelectric conversion efficiency of crystalline silicon cells needs to be further improved. Summary of the Invention

[0003] Based on this, the present application provides a crystalline silicon textured structure, a battery and a preparation method thereof, and a photovoltaic module that can effectively improve the photoelectric conversion efficiency.

[0004] The technical solution of this application to solve the above technical problems is as follows.

[0005] In a first aspect, the present application provides a crystalline silicon velvet structure, which includes a silicon substrate and a pyramid-like structure arranged on the silicon substrate. The pyramid-like structure includes a first part and a second part, the first part is located on a side of the second part away from the silicon substrate, the first part has a first side surface, the first side surface is a concave structure, and the first part is a spike structure.

[0006] In some embodiments, in the crystalline silicon textured structure, the second portion has a second side surface connected to the first side surface, and the maximum value of the distance from a point on the first side surface to an extension surface of the second side surface is d, 10 nm≤d≤200 nm.

[0007] In some embodiments, in the crystalline silicon textured structure, the crystalline silicon textured structure satisfies at least one of the following characteristics:

[0008] (1) The distance between the endpoints of two adjacent side edges of the second portion away from the silicon substrate is L1, 50 nm ≤ L1 ≤ 200 nm;

[0009] (2) The distance between the endpoints of two adjacent side edges in the second portion close to the silicon substrate is L2, 1000 nm ≤ L2 ≤ 3000 nm.

[0010] In some embodiments, in the crystalline silicon textured structure, an angle α between at least one side edge of the second portion and the silicon substrate is 56°≤α≤68°.

[0011] In some embodiments, in the crystalline silicon textured structure, along the vertical direction of the silicon substrate, the height of the first portion is h1, the height of the second portion is h2, and the crystalline silicon textured structure satisfies at least one of the following characteristics:

[0012] (1)10 nm≤h1≤1000 nm;

[0013] (2) 500nm≤h2≤2000nm;

[0014] (3) 0.02≤h1 / h2≤1.

[0015] The second aspect of the present application provides a method for preparing the crystalline silicon textured structure provided in the first aspect, comprising the following steps:

[0016] A first texturing treatment and a second texturing treatment are sequentially performed on at least one surface of the silicon wafer, wherein the texturing agent used in the second texturing treatment includes sodium lignin sulfonate and benzotriazole.

[0017] In some embodiments, in the preparation method of the crystalline silicon textured structure, the texturing agent includes the following components, calculated by weight: 0.2-0.3 parts of 2-methyl-2,4-pentanediol, 1.5-2 parts of sodium carboxymethyl cellulose, 0.18-0.22 parts of 5-nitroguaiacol, 0.2-0.25 parts of triclosan, 0.3-0.5 parts of sodium hydroxide, 0.1-0.15 parts of poly[sodium naphthalene formaldehyde sulfonate], 0.2-0.7 parts of sodium lignin sulfonate, 0.1-0.3 parts of benzotriazole, 0.05-0.15 parts of sodium acetate, 0.2-0.4 parts of sodium chloride and 95-96.97 parts of water.

[0018] In some embodiments, in the method for preparing a crystalline silicon textured structure, the method for preparing a crystalline silicon textured structure satisfies at least one of the following characteristics:

[0019] (1) In the texturing agent, the mass fraction of the sodium lignin sulfonate is greater than the mass fraction of the benzotriazole;

[0020] (2) In the texturing agent, the mass fraction of the sodium lignin sulfonate is 0.3 to 0.7 parts;

[0021] (3) In the texturing agent, the mass fraction of the benzotriazole is 0.2 to 0.3 parts;

[0022] (4) The temperature of the second texturing treatment is 68°C to 76°C, and the time is 80s to 160s.

[0023] The third aspect of the present application provides a battery, comprising a silicon substrate and a metal electrode, wherein at least one surface of the silicon substrate comprises a metal contact area, the metal electrode is arranged in the metal contact area, and the metal contact area comprises the crystalline silicon velvet structure provided by the first aspect or the crystalline silicon velvet structure prepared by the preparation method of the crystalline silicon velvet structure provided by the second aspect.

[0024] In some embodiments, in the battery, the surface of the silicon substrate further includes a non-metallic contact region, and the non-metallic contact region includes the crystalline silicon textured structure.

[0025] In some embodiments, in the battery, the thickness of the silicon substrate in the metal contact area is δ1, and the thickness of the silicon substrate in the non-metal contact area is δ2, where δ1>δ2.

[0026] In some embodiments, in the battery, δ1-δ2=0.5 μm~15 μm.

[0027] In some embodiments, in the battery, the total area of ​​the non-metallic contact regions is S1, the total area of ​​the metal contact regions is S2, and S1>S2.

[0028] In some embodiments, in the battery, the silicon substrate is doped with a boron group element, the doping concentration of the boron group element in the metal contact region is C1, the doping concentration of the boron group element in the non-metal contact region is C2, and C1>C2.

[0029] In some embodiments, in the battery, the boron group element is independently selected from at least one of boron, aluminum, gallium, and indium.

[0030] In some embodiments, in the battery, the silicon substrate includes a front side and a back side, and the battery satisfies at least one of the following characteristics:

[0031] (1) The battery comprises a tunneling oxide layer and a polysilicon layer, wherein the tunneling oxide layer is provided on the back side of the silicon substrate, and the polysilicon layer is provided on a side of the tunneling oxide layer away from the silicon substrate;

[0032] (2) The cell includes a passivation layer and an anti-reflection layer, wherein the passivation layer is arranged on the front surface of the silicon substrate, and the anti-reflection layer is arranged on the side of the passivation layer away from the silicon substrate.

[0033] A fourth aspect of the present application provides a method for preparing the battery provided in the third aspect, comprising the following steps:

[0034] Providing a silicon wafer, wherein at least one surface of the silicon wafer comprises a metal contact area;

[0035] performing a first texturing treatment and a second texturing treatment in sequence on the metal contact area of ​​the silicon wafer; the texturing agent used in the second texturing treatment includes sodium lignin sulfonate and benzotriazole;

[0036] A metal electrode is prepared in the metal contact area.

[0037] In some embodiments, the method for preparing a battery includes the following steps:

[0038] Performing a first texturing treatment and a second texturing treatment on both surfaces of the silicon wafer in sequence;

[0039] performing diffusion processing on the silicon wafer using a semiconductor source;

[0040] Laser molding the non-metallic contact area on the front side of the silicon wafer;

[0041] Performing a third texturing treatment on the non-metallic contact area after the laser mold opening;

[0042] performing double-sided oxidation treatment on the silicon wafer;

[0043] performing back polishing on the silicon wafer;

[0044] sequentially preparing a tunnel oxide layer and a polysilicon layer on the back side of the silicon wafer;

[0045] A passivation layer and an anti-reflection layer are sequentially prepared on both surfaces of the silicon wafer;

[0046] A metal electrode is prepared in the metal contact area of ​​the silicon wafer.

[0047] In some embodiments, in the method for preparing a battery, the step of preparing the metal electrode includes: applying a metal conductive paste to the metal contact area of ​​the silicon wafer, and then performing LECO laser-assisted sintering.

[0048] A fifth aspect of the present application provides a photovoltaic module, comprising the battery provided in the third aspect or a battery produced by the method for producing the battery provided in the fourth aspect.

[0049] The crystalline silicon textured structure of the present application has the following beneficial effects:

[0050] The crystalline silicon velvet structure provided in the present application includes a silicon substrate and a pyramid-like structure arranged on the silicon substrate. The pyramid-like structure includes a first part and a second part. The first part is located on the side of the second part away from the silicon substrate. The first part has a first side surface with a concave structure. The first part has a spike structure, which can provide contact points that are easy to transmit current, thereby improving the fill factor of the battery and further improving the photoelectric conversion efficiency of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0052] Figure 1 A schematic side view of a pyramid-like structure provided in one embodiment;

[0053] Figure 2 A schematic structural diagram of a battery provided in one embodiment;

[0054] Figure 3 The SEM image of the pyramid-like structure provided in Example 1;

[0055] Figure 4 This is an SEM image of the standard pyramid structure provided for Comparative Example 1.

[0056] Reference numerals:

[0057] 10: Battery; 11: Silicon substrate; 111: Silicon base; 112: Pyramid-like structure; 12: Metal electrode; 121: Front electrode; 122: Back electrode; 13: Tunneling oxide layer; 14: Polysilicon layer; 15: Passivation layer; 16: Anti-reflection layer. DETAILED DESCRIPTION

[0058] Below in conjunction with embodiment and example, the application is described in further detail.It should be understood that these embodiment and example are only used to illustrate the application and are not used to limit the scope of the application. The purpose of providing these embodiment and example is to make the understanding of the disclosure of the application more thorough and comprehensive.It should also be understood that the application can be implemented in many different forms and is not limited to the embodiment and example described herein. Those skilled in the art can make various changes or modifications without violating the connotation of the application, and the equivalent form obtained also falls within the protection scope of the application.For example, the feature described or described as part of one embodiment can be combined in another embodiment in a suitable manner to produce a new embodiment.In addition, in the description below, a large amount of specific details are given in order to provide a more comprehensive understanding of the application.It should be understood that the application can be implemented without one or more of these details.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing embodiments and examples only and are not intended to limit this application.

[0060] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0061] In this application, "plurality", "multiple", "multiple times", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0062] As used herein, "combination thereof", "any combination thereof", "any combination thereof" and the like include all suitable combinations of any two or more of the listed items.

[0063] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc. shall be based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0064] Herein, the terms "preferred," "better," "more preferred," and "suitable" are used solely to describe preferred implementations or examples and should not be construed as limiting the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, each "preferred" term is considered independent unless otherwise specified and there are no contradictions or mutual constraints.

[0065] In this application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0066] In this application, the terms "optionally," "optional," and "optional" mean optional or dispensable, i.e., they refer to either option being selected from two parallel options: "with" or "without." If a technical solution contains multiple "optional" clauses, each "optional" clause is independent unless otherwise specified and there are no contradictions or constraints.

[0067] In this application, the terms "first," "second," "third," "fourth," etc. in "the first aspect," "the second aspect," "the third aspect," "the fourth aspect," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or quantity, nor should they be understood as implicitly indicating the importance or quantity of the indicated technical features. Furthermore, "first," "second," "third," "fourth," etc. serve only as non-exhaustive enumeration and description, and should be understood not to constitute a closed-ended limitation on quantity.

[0068] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0069] In this application, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​within the numerical interval is deemed to be continuous and includes the two numerical endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two numerical endpoints. Unless otherwise specified, when a numerical interval refers only to integers within the numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe a feature or characteristic, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. "Numerical interval" allows for a broad range of numerical interval types including percentage intervals, ratio intervals, and ratio intervals.

[0070] Unless otherwise specified, the temperature parameters in this application allow for both constant temperature treatment and temperature fluctuations within a certain temperature range. It should be understood that the constant temperature treatment allows for temperature fluctuations within the accuracy range of instrument control. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are permitted.

[0071] In this application, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0072] In this application, when referring to a range of units, if the unit is only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 3~5h means that the units of the left endpoint "3" and the right endpoint "5" are both hours.

[0073] All documents mentioned in this application are cited as references in this application, just as each document is cited as a reference individually. Unless they conflict with the invention purpose and / or technical solution of this application, the cited documents involved in this application are cited in their entirety and for all purposes. When cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When cited documents are involved in this application, the examples and preferred embodiments of the cited relevant technical features may also be incorporated into this application as references, but are limited to the ability to implement this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be adaptively amended according to the description in this application.

[0074] The mass or weight of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the proportional relationship of the mass or weight of each component. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass or weight described in the examples of this application may be units known in the chemical industry such as μg, mg, g, and kg.

[0075] One embodiment of the present application provides a crystalline silicon velvet structure, which includes a silicon substrate and a pyramid-like structure arranged on the silicon substrate. The pyramid-like structure includes a first part and a second part. The first part is located on a side of the second part away from the silicon substrate. The first part has a first side surface, the first side surface is a concave structure, and the first part is a spike structure.

[0076] The crystalline silicon velvet structure of the present application includes a silicon substrate and a pyramid-like structure. The pyramid-like structure includes a first part and a second part. The first part is located on the side of the second part away from the silicon substrate. The first part has a first side surface with a concave structure. The first part has a spike structure, which can provide contact points that are easy to transmit current, thereby improving the fill factor of the battery and further improving the photoelectric conversion efficiency of the battery.

[0077] It can be understood that in the pyramid-like structure, the first part is the top part of the pyramid-like structure, and the second part is the bottom part of the pyramid-like structure.

[0078] The shape of a traditional pyramid is a quadrangular pyramid with a square base and four triangular sides. Among the individual sides, the side of the top of the pyramid is on the same plane as the side of the base of the pyramid. However, in the pyramid structure of the present application, the side of the first part is a concave structure and is not on the same plane as the side of the corresponding second part. There is a gap between the planes where the side of the first part and the side of the second part are located.

[0079] See also Figure 1 , which is a schematic side view of a pyramid-like structure. In some examples, in the crystalline silicon textured structure, the second portion has a second side surface, which is connected to the first side surface. The maximum distance between a point on the first side surface and an extension of the second side surface is d, and 10 nm ≤ d ≤ 200 nm.

[0080] It can be understood that the distance between a point and a surface refers to the length of the line segment between a point and the foot of the perpendicular, which is the distance from the point to the surface. d can be understood as the maximum depth of the concavity of the first side surface.

[0081] It will be understood that d includes but is not limited to 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, and 200 nm; in some examples, d may be within a range consisting of any two of these point values ​​as end values, the same below; for example, 10 nm≤d≤180 nm, 50 nm≤d≤180 nm, 100 nm≤d≤180 nm, 50 nm≤d≤200 nm, 100 nm≤d≤200 nm, 100 nm≤d≤150 nm, etc.

[0082] By controlling the maximum value d of the distance from a point on the first side surface to the extended surface of the second side surface, the fill factor (FF) of the battery can be increased, thereby improving the photoelectric conversion efficiency.

[0083] In some examples, in the crystalline silicon textured structure, a distance between endpoints of two adjacent side edges in the second portion away from the silicon substrate is L1, and 50 nm≤L1≤200 nm.

[0084] It is understood that a side edge is a straight line segment connecting two adjacent side vertices of a polyhedron. In a quadrangular pyramid structure, a side edge refers to the four edge lines connecting the vertex and each vertex of the bottom quadrilateral, that is, a side edge refers to the intersection of the side surfaces. It is further understood that L1 includes but is not limited to 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 195 nm, and 200 nm.

[0085] In some of the examples, in the crystalline silicon textured structure, a distance between endpoints of two adjacent side edges in the second portion close to the silicon substrate is L2, and 1000 nm≤L2≤3000 nm.

[0086] It will be understood that L2 includes but is not limited to 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, 2000 nm, 2100 nm, 2200 nm, 2300 nm, 2400 nm, 2500 nm, 2600 nm, 2700 nm, 2800 nm, 2900 nm, and 3000 nm.

[0087] It can be understood that L2 affects the size of a single pyramid-like structure, the open circuit voltage Voc is positively correlated with L2, and the fill factor FF is negatively correlated with L2; by controlling L2 within the above range, Voc and FF can be balanced, so that the comprehensive performance of Voc and FF is better, thereby further improving the photoelectric conversion efficiency of the battery.

[0088] In some examples, in the crystalline silicon textured structure, an angle α between at least one side edge of the second portion and the silicon substrate is 56°≤α≤68°.

[0089] It can be understood that the angle between a line and a plane refers to the angle formed by the intersection of a line perpendicular to the plane at a point on the line, the line connecting the intersection of the line and the plane, and the original line (the complementary angle of the angle between the line and the plane). This angle is also called the line-to-plane angle. Examples of α include, but are not limited to, 56°, 57°, 58°, 59°, 60°, 61°, 62°, 63°, 64°, 65°, 66°, 67°, and 68°.

[0090] It can be understood that α affects the reflection angle of the incident light, and the absorption of the incident light is positively correlated with the reflection angle, thereby affecting the photoelectric conversion efficiency.

[0091] In some examples, in the crystalline silicon textured structure, along the vertical direction of the silicon substrate, the height of the first portion is h1, and the height of the second portion is h2.

[0092] Optionally, 10 nm≤h1≤1000 nm. It is understood that h1 includes but is not limited to 10 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, and 1000 nm.

[0093] Optionally, 500 nm ≤ h2 ≤ 2000 nm. It will be understood that h2 includes but is not limited to 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, and 2000 nm.

[0094] In some examples, in the crystalline silicon textured structure, 0.02≤h1 / h2≤1. It is understood that h1 / h2 includes but is not limited to 0.02, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1. Optionally, 0.02≤h1 / h2≤0.3.

[0095] It can be understood that L1, α and h1 / h2 affect the volume of the first part of the pyramid-like structure. On the basis of controlling d and keeping L1, α and h1 / h2 within the above range, the photoelectric conversion efficiency is positively correlated with the volume.

[0096] An embodiment of the present application provides a method for preparing a crystalline silicon textured structure, comprising the following steps:

[0097] A first texturing treatment and a second texturing treatment are sequentially performed on at least one surface of the silicon wafer, wherein a texturing agent (second texturing agent) used in the second texturing treatment includes sodium lignin sulfonate and benzotriazole.

[0098] After the first texturing treatment of the silicon wafer, a second texturing treatment is performed using a texturing agent containing specific components. Benzotriazole is adsorbed on the growth position of sodium lignin sulfonate, resulting in selective etching to obtain a crystalline silicon textured structure. The crystalline silicon textured structure includes a silicon substrate and a pyramid-like structure. The pyramid-like structure includes a first part and a second part. The first part is located on the side of the second part away from the silicon substrate. The first part has a first side surface with a concave structure. The first part has a spike structure, which can provide contact points that are easy to transmit current, thereby improving the fill factor of the battery and further improving the photoelectric conversion efficiency of the battery.

[0099] Furthermore, no water tank is required between the two-step texturing process, and the yield rate is not deteriorated. It can be understood that the preparation method of the crystalline silicon textured structure provided in this application can obtain the above-mentioned crystalline silicon textured structure.

[0100] It can be understood that the silicon wafer includes a front side and a back side, and at least one surface of the silicon wafer includes a front side, a back side, or both a front side and a back side.

[0101] In some examples, in the method for preparing a crystalline silicon textured structure, the mass fraction of sodium lignin sulfonate in the texturing agent used in the second texturing treatment is greater than the mass fraction of benzotriazole.

[0102] In some of the examples, in the method for preparing the crystalline silicon textured structure, the texturing agent used in the second texturing treatment has a mass fraction of sodium lignin sulfonate of 0.2-0.7 parts and a mass fraction of benzotriazole of 0.1-0.3 parts.

[0103] It can be understood that in the texturing agent used in the second texturing treatment, the mass fractions of sodium lignin sulfonate include but are not limited to 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, and 0.7 parts; the mass fractions of benzotriazole include but are not limited to 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, and 0.3 parts.

[0104] In some of the examples, in the method for preparing the crystalline silicon textured structure, the texturing agent used in the second texturing treatment also includes at least one of 2-methyl-2,4-pentanediol, sodium carboxymethyl cellulose, 5-nitroguaiacol, triclosan, sodium hydroxide, poly[sodium naphthaldehyde sulfonate], sodium acetate and sodium chloride.

[0105] Furthermore, in the preparation method of the crystalline silicon textured structure, the texturing agent used in the second texturing treatment also includes 2-methyl-2,4-pentanediol, sodium carboxymethyl cellulose, 5-nitroguaiacol, triclosan, sodium hydroxide, poly[sodium naphthalene formaldehyde sulfonate], sodium acetate and sodium chloride.

[0106] In some of the examples, in the preparation method of the crystalline silicon textured structure, the texturing agent used in the second texturing treatment includes the following components, calculated by mass: 0.2~0.3 parts of 2-methyl-2,4-pentanediol, 1.5~2 parts of sodium carboxymethyl cellulose, 0.18~0.22 parts of 5-nitroguaiacol, 0.2~0.25 parts of triclosan, 0.3~0.5 parts of sodium hydroxide, 0.1~0.15 parts of poly[sodium naphthalene formaldehyde sulfonate], 0.2~0.7 parts of sodium lignin sulfonate, 0.1~0.3 parts of benzotriazole, 0.05~0.15 parts of sodium acetate, 0.2~0.4 parts of sodium chloride and 95~96.97 parts of water.

[0107] It can be understood that, in terms of weight, in the texturing agent used in the second texturing treatment, 2-methyl-2,4-pentanediol includes but is not limited to 0.2 parts, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts, and 0.3 parts; sodium carboxymethyl cellulose includes but is not limited to 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, and 2 parts; 5-nitroguaiacol includes but is not limited to 0.18 parts, 0.19 parts, 0.2 parts, 0.21 parts, and 0.22 parts; triclosan includes but is not limited to 0.2 parts, 0.21 parts, and 0.21 parts. , 0.22, 0.23, 0.24, 0.25 parts; sodium hydroxide includes but is not limited to 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5 parts; sodium poly [(naphthaldehyde) sulfonate] includes but is not limited to 0.1, 0.11, 0.12, 0.13, 0.14, 0.15 parts; sodium lignin sulfonate includes but is not limited to 0.2, 0.25, 0.3, 0 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts; benzotriazole includes but is not limited to 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts; sodium acetate includes but is not limited to 0.05 parts, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts; sodium chloride includes but is not limited to 0.2 parts, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts, 0.3 parts, 0.32 parts, 0.34 parts, 0.36 parts, 0.38 parts, 0.4 parts; water includes but is not limited to 95.0 parts, 95.1 parts, 95.2 parts, 95.3 parts, 95.4 parts, 95.5 parts, 95.6 parts, 95.7 parts, 95.8 parts, 95.9 parts, 96.0 parts, 96.1 parts, 96.2 parts, 96.3 parts, 96.4 parts, 96.5 parts, 96.6 parts, 96.7 parts, 96.8 parts, 96.9 parts, 96.97 parts.

[0108] In some of the examples, in the method for preparing a crystalline silicon textured structure, the texturing agent used in the second texturing treatment is composed of the following components, calculated by mass: 0.2~0.3 parts of 2-methyl-2,4-pentanediol, 1.5~2 parts of sodium carboxymethyl cellulose, 0.18~0.22 parts of 5-nitroguaiacol, 0.2~0.25 parts of triclosan, 0.3~0.5 parts of sodium hydroxide, 0.1~0.15 parts of poly[sodium naphthalene formaldehyde sulfonate], 0.2~0.7 parts of sodium lignin sulfonate, 0.1~0.3 parts of benzotriazole, 0.05~0.15 parts of sodium acetate, 0.2~0.4 parts of sodium chloride and 95~96.97 parts of water.

[0109] In some of the examples, in the method for preparing a crystalline silicon textured structure, the texturing agent used in the second texturing treatment includes the following components, calculated by mass percentage: 0.2%~0.3% of 2-methyl-2,4-pentanediol, 1.5%~2% of sodium carboxymethyl cellulose, 0.18%~0.22% of 5-nitroguaiacol, 0.2%~0.25% of triclosan, 0.3%~0.5% of sodium hydroxide, 0.1%~0.15% of poly[sodium naphthaldehyde sulfonate], 0.2%~0.7% of sodium lignin sulfonate, 0.1%~0.3% of benzotriazole, 0.05%~0.15% of sodium acetate, 0.2%~0.4% of sodium chloride and 95%~96.97% of water.

[0110] In some of the examples, in the method for preparing the crystalline silicon textured structure, the mass concentration of sodium lignin sulfonate in the texturing agent used in the second texturing treatment is 0.3%~0.7%.

[0111] It is understood that the mass concentration of sodium lignin sulfonate includes but is not limited to 0.3%, 0.4%, 0.5%, 0.6%, and 0.7%.

[0112] In some of the examples, in the method for preparing the crystalline silicon textured structure, the mass concentration of benzotriazole in the texturing agent used in the second texturing treatment is 0.2%~0.3%.

[0113] It will be appreciated that the mass concentration of benzotriazole includes, but is not limited to, 0.2%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, and 0.3%.

[0114] It can be understood that in some of these examples, the texturing agent used in the second texturing treatment also includes a pigment.

[0115] In some examples, in the method for preparing a crystalline silicon textured structure, the temperature of the second texture treatment is 68° C. to 76° C., and the time is 80 seconds to 160 seconds.

[0116] It is understood that the temperature of the second texturing process includes, but is not limited to, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, and 76°C, and the time includes, but is not limited to, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, and 160s. By controlling the temperature and time of the second texturing process, the maximum value d of the distance from a point on the first side surface to the extended surface of the second side surface can be controlled.

[0117] In some of the examples, in the method for preparing a crystalline silicon textured structure, the texturing agent (first texturing agent) used in the first texturing treatment includes the following components: 2-methyl-2,4-pentanediol, sodium carboxymethyl cellulose, 5-nitroguaiacol, triclosan, sodium hydroxide, sodium acetate and sodium chloride.

[0118] In some examples, in the method for preparing a crystalline silicon textured structure, the texturing agent used in the first texturing treatment includes the following components in parts by mass:

[0119] 0.2-0.3 parts of 2-methyl-2,4-pentanediol, 1.5-2 parts of sodium carboxymethyl cellulose, 0.18-0.22 parts of 5-nitroguaiacol, 0.2-0.25 parts of triclosan, 0.3-0.5 parts of sodium hydroxide, 0.15-0.25 parts of sodium acetate, 0.2-0.4 parts of sodium chloride and 96.08-97.27 parts of water.

[0120] It can be understood that, in terms of weight, in the texturing agent used in the first texturing treatment, 2-methyl-2,4-pentanediol includes but is not limited to 0.2 parts, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts, and 0.3 parts; sodium carboxymethyl cellulose includes but is not limited to 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, and 2 parts; 5-nitroguaiacol includes but is not limited to 0.18 parts, 0.19 parts, 0.2 parts, 0.21 parts, and 0.22 parts; triclosan includes but is not limited to 0.2 parts, 0.21 parts, 0.22 parts, 0.23 parts, 0.24 parts, 0.25 parts; sodium hydroxide includes but is not limited to 0.3 parts, 0.32 parts, 0.34 parts, 0.36 parts, 0.38 parts, 0.4 parts, 0.42 parts, 0.44 parts, 0.46 parts, 0.48 parts, and 0.5 parts; sodium acetate includes but is not limited to 0.15 parts, 0.16 parts, 0.18 parts, 0.2 parts, 0.22 parts, 0.24 parts, and 0.25 parts; sodium chloride includes but is not limited to 0.2 parts, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts, 0.3 parts, 0.32 parts, 0.34 parts, 0.36 parts, 0.38 parts, and 0.4 parts.

[0121] In some examples, in the method for preparing a crystalline silicon textured structure, the texturing agent used in the first texturing treatment includes the following components, calculated by mass percentage:

[0122] 2-Methyl-2,4-pentanediol 0.2%~0.3%, sodium carboxymethyl cellulose 1.5%~2%, 5-nitroguaiacol 0.18%~0.22%, triclosan 0.2%~0.25%, sodium hydroxide 0.3%~0.5%, sodium acetate 0.15%~0.25%, sodium chloride 0.2%~0.4% and water as the balance.

[0123] In some of these examples, the texturing agent used in the first texturing treatment also includes a pigment.

[0124] In some examples, in the method for preparing the crystalline silicon textured structure, the temperature of the first texture treatment is 80° C. to 86° C., and the time is 300 s to 360 s.

[0125] It can be understood that the temperature of the first texturing treatment includes but is not limited to 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, and 86℃, and the time includes but is not limited to 300s, 310s, 320s, 330s, 340s, 350s, and 360s.

[0126] See also Figure 2 In one embodiment of the present application, a battery 10 is provided, comprising a silicon substrate 11 and a metal electrode 12. At least one surface of the silicon substrate 11 comprises a metal contact area. The metal electrode 12 is arranged in the metal contact area. The metal contact area comprises the above-mentioned crystalline silicon velvet structure or the crystalline silicon velvet structure obtained by the preparation method of the above-mentioned crystalline silicon velvet structure.

[0127] The battery provided in the present application, wherein the metal contact region includes the above-mentioned crystalline silicon velvet structure or the crystalline silicon velvet structure prepared by the above-mentioned preparation method of the crystalline silicon velvet structure, can effectively improve the fill factor of the battery, thereby effectively improving the photoelectric conversion efficiency of the battery.

[0128] It is understood that in some examples, the metal contact region of the silicon substrate 11 of the battery 10 is the aforementioned crystalline silicon textured structure. Furthermore, the metal contact region of the silicon substrate 11 includes a silicon base 111 and a pyramid-like structure 112. The pyramid-like structure 112 includes a first portion and a second portion. The first portion is located on a side of the second portion away from the silicon base 111. The first portion has a first side surface, and the first side surface is a concave structure.

[0129] In some examples, in the battery 10 , the surface of the silicon substrate 11 further includes a non-metallic contact region.

[0130] It is understood that the area of ​​the silicon substrate 11 that contacts the metal electrode 12 is the metal contact area, and the area that does not contact the metal electrode 12 is the non-metal contact area. Furthermore, the present application does not limit the texture structure of the non-metal contact area of ​​the silicon substrate 11, which can be the above-mentioned crystalline silicon texture structure or a traditional texture structure.

[0131] In some examples, in the battery 10 , the non-metallic contact region includes the aforementioned crystalline silicon textured structure.

[0132] In some examples, in the battery 10, the thickness of the silicon substrate 11 in the metal contact area and the thickness of the silicon substrate 11 in the non-metal contact area are independently 80 μm to 250 μm. It is understood that the thickness of the silicon substrate 11 in the metal contact area and the thickness of the silicon substrate 11 in the non-metal contact area include, but are not limited to, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, and 250 μm.

[0133] In some examples, in the battery 10 , the thickness of the silicon substrate 11 in the metal contact region is δ1, and the thickness of the silicon substrate 11 in the non-metal contact region is δ2, where δ1>δ2.

[0134] It is understood that in some examples, in battery 10, the non-metallic contact area on the front side of silicon substrate 11 is lower than the metal contact area on the front side of silicon substrate 11. That is, on the front side of silicon substrate 11, the metal contact area protrudes more than the non-metallic contact area. Furthermore, on the front side of silicon substrate 11, the metal contact area protrudes more than the non-metallic contact area by δ1-δ2.

[0135] In some of these examples, in the battery 10 , δ1 − δ2 = 0.5 μm to 15 μm.

[0136] It can be understood that δ1-δ2 includes, but is not limited to, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm.

[0137] In some of these examples, in the battery 10 , δ1 − δ2 = 0.5 μm to 10 μm.

[0138] Graphically shaping the front emitter of the battery while controlling the height difference (δ1-δ2) can reduce Auger recombination and improve the battery's Voc, FF and Isc.

[0139] In some examples, in the battery 10 , the total area of ​​the non-metal contact region is S1 , the total area of ​​the metal contact region is S2 , and S1 > S2 .

[0140] In some examples, in the battery 10 , the silicon substrate 11 is doped with boron group elements, the doping concentration of the boron group elements in the metal contact region is C1, and the doping concentration of the boron group elements in the non-metal contact region is C2, where C1>C2.

[0141] It can be understood that the doping concentration C1 refers to the average concentration of the boron group elements doped in the silicon substrate 11 in the entire metal contact area, and the doping concentration C2 refers to the average concentration of the boron group elements doped in the silicon substrate 11 in the entire non-metal contact area.

[0142] It can be understood that the boron group elements are a column of elements located in Group IIIA of the periodic table.

[0143] In some examples, in the battery 10 , the boron group element is independently selected from at least one of boron, aluminum, gallium, and indium.

[0144] It can be understood that the silicon substrate 11 includes a front side and a back side.

[0145] In some examples, in the battery 10 , the front surface of the silicon substrate 11 includes the above-mentioned crystalline silicon textured structure.

[0146] In some examples, the cell 10 includes at least one of an HJT cell (heterojunction cell), a TOPCon cell (tunneling oxide passivated contact cell), a BC cell (back contact cell), and a PERC cell (passivated emitter and rear cell).

[0147] In some examples, battery 10 is a TOPCon battery.

[0148] In some examples, the battery 10 includes a tunneling oxide layer 13 and a polysilicon layer 14 . The tunneling oxide layer 13 is disposed on the back side of the silicon substrate 11 , and the polysilicon layer 14 is disposed on a side of the tunneling oxide layer 13 away from the silicon substrate 11 .

[0149] In some examples, the cell 10 includes a passivation layer 15 and an anti-reflection layer 16 . The passivation layer 15 is disposed on the front surface of the silicon substrate 11 , and the anti-reflection layer 16 is disposed on a side of the passivation layer 15 away from the silicon substrate 11 .

[0150] In some examples, in the cell 10 , a passivation layer 15 and an anti-reflection layer 16 are sequentially provided on a surface of the polysilicon layer 14 away from the tunneling oxide layer 13 .

[0151] In some examples, in the battery 10 , the metal electrode 12 includes a front electrode 121 and a back electrode 122 .

[0152] In some examples, the cell 10 includes a back electrode 122, an anti-reflection layer 16, a passivation layer 15, a polysilicon layer 14, a tunneling oxide layer 13, a silicon substrate 11, a passivation layer 15, an anti-reflection layer 16 and a front electrode 121 stacked from the back to the front.

[0153] In some examples, in the cell 10 , the front electrode 121 penetrates the passivation layer 15 and the anti-reflection layer 16 to connect to the front surface of the silicon substrate 11 , and the back metal electrode 122 penetrates the tunneling oxide layer 13 to connect to the polysilicon layer 14 .

[0154] It is understood that the present application does not limit the types of the metal electrode 12, tunnel oxide layer 13, polysilicon layer 14, passivation layer 15, and anti-reflection layer 16, as long as they are achievable. For example, the tunnel oxide layer 13 includes SiO2, and the passivation layer 15 and anti-reflection layer 16 each independently include, but are not limited to, at least one of a polysilicon layer, a metal oxide layer, a non-metallic oxide, a nitride, and an oxynitride.

[0155] An embodiment of the present application provides a method for preparing a battery, comprising the following steps:

[0156] Providing a silicon wafer, wherein at least one surface of the silicon wafer includes a metal contact area;

[0157] The metal contact area of ​​the silicon wafer is sequentially subjected to a first texturing treatment and a second texturing treatment; the texturing agent used in the second texturing treatment includes sodium lignin sulfonate and benzotriazole;

[0158] Metal electrodes are prepared in the metal contact area.

[0159] The preparation method of the battery provided in the present application produces a crystalline silicon textured structure in the metal contact area, which can effectively improve the fill factor of the battery and thus effectively improve the photoelectric conversion efficiency of the battery.

[0160] It can be understood that in the battery preparation method, the first texturing treatment and the second texturing treatment are sequentially performed on the metal contact area of ​​the silicon wafer, which are mutually applicable to the features of the above-mentioned method for preparing the crystalline silicon textured structure and will not be elaborated here.

[0161] In some of these examples, a metal conductive paste is used to prepare a metal electrode in a battery preparation method.

[0162] On the basis of the first texturing treatment on the silicon wafer, a second texturing treatment is performed using a texturing agent containing specific components to generate a pyramid-like structure. The pyramid-like structure includes a first part and a second part. The first part is located on the side of the second part away from the silicon substrate. The first part has a first side surface, and the first side surface is a concave structure.

[0163] By controlling the maximum value d of the distance from a point on the first side to the extended surface of the second side, the contact point between the first part of the pyramid-like structure and the slurry can be enhanced, the filling factor of the battery can be improved, and the photoelectric conversion efficiency can be improved.

[0164] In some examples, the method for preparing a battery includes the following steps:

[0165] Step S100: performing a first texturing treatment and a second texturing treatment on both surfaces of the silicon wafer in sequence.

[0166] It can be understood that step S100 includes performing the first texturing treatment and the second texturing treatment on the front side of the silicon wafer in sequence, and performing the first texturing treatment and the second texturing treatment on the back side of the silicon wafer in sequence; further, the texturing area includes the metal contact area and the non-metal contact area on the front side, and the metal contact area and the non-metal contact area on the back side.

[0167] Step S200: performing diffusion processing on the silicon wafer using a semiconductor source.

[0168] In some examples, in step S200 , the semiconductor source includes at least one of a boron source, an aluminum source, a gallium source, and an indium source.

[0169] It is understood that in step S200, the diffusion process causes the boron group element in the semiconductor source to be doped into the silicon wafer, and simultaneously forms a mask layer on both surfaces of the silicon wafer. For example, in some examples, the semiconductor source includes boron oxide, and the silicon on the silicon wafer surface reacts with the boron oxide to form a borosilicate glass layer (BSG mask layer).

[0170] Step S300: performing laser molding on the non-metallic contact area on the front side of the silicon wafer.

[0171] It can be understood that step S300 of laser-molding the non-metallic contact area on the front side of the silicon wafer is to remove the mask layer formed on the non-metallic contact area on the front side of the silicon wafer in step S200.

[0172] Step S400: performing a third texturing process on the non-metallic contact area after the laser mold opening.

[0173] It can be understood that step S100 simultaneously performs texturing on the metal contact area and the non-metal contact area, and at this time, the metal contact area and the non-metal contact area are simultaneously etched and thinned; steps S300 to S400 again and only perform laser molding and texturing on the non-metal contact area, and at this time, the non-metal contact area undergoes a second etching and thinning, resulting in a height difference between the metal contact area and the non-metal contact area of ​​the silicon wafer; further, in the direction of battery thickness, the non-metal contact area on the front side of the silicon wafer is lower than the metal contact area on the front side of the silicon wafer, that is, on the front side of the silicon wafer, the metal contact area is more protruding than the non-metal contact area.

[0174] In some examples, in step S400, the temperature of the third texturing treatment is 65°C to 85°C. It is understood that the temperature of the third texturing treatment includes but is not limited to 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, and 85°C. Furthermore, the time of the third texturing treatment is 50s to 500s. It is understood that the time of the third texturing treatment includes but is not limited to 50s, 100s, 150s, 200s, 250s, 300s, 350s, 400s, 450s, and 500s. By controlling the temperature and time of the third texturing treatment, δ1-δ2 can be controlled.

[0175] Step S500: performing double-sided oxidation treatment on the silicon wafer.

[0176] It is understandable that the oxidation treatment will generate a silicon oxide layer, which will protect the velvet surface on the front side when the silicon wafer is subsequently back-polished.

[0177] Step S600: back-polishing the silicon wafer.

[0178] It can be understood that step S600 performs back polishing on the silicon wafer to remove the silicon oxide layer generated on the back side of the silicon wafer (including the metal contact area and the non-metal contact area) in step S500, the mask layer formed on the back side of the silicon wafer (including the metal contact area and the non-metal contact area) in step S200, and the crystalline silicon texture structure formed by the first texture treatment and the second texture treatment.

[0179] Furthermore, the present application does not impose any restrictions on the polishing liquid used for back polishing, and the back polishing of the silicon wafer can be performed.

[0180] Step S700: sequentially preparing a tunnel oxide layer and a polysilicon layer on the back side of the silicon wafer.

[0181] In some examples, in step S700, preparing the tunnel oxide layer and the polysilicon layer includes:

[0182] Step S710: using PECVD (plasma enhanced chemical vapor deposition) to form a tunneling oxide layer on the back side of the silicon wafer; optionally, using N2O to react with Si to deposit a SiO2 tunneling oxide layer;

[0183] Step S720: depositing a Poly-Si film using PECVD; optionally, the reaction gases include SiH4, H2, and PH3;

[0184] Step S730: performing annealing treatment on the silicon wafer.

[0185] It can be understood that during the annealing process, the initially deposited amorphous silicon film is completely crystallized to form a polysilicon structure, while the doping atoms are activated.

[0186] In some other examples, in step S700, preparing the tunnel oxide layer and the polysilicon layer includes:

[0187] Step S740: growing a tunnel oxide layer using LPCVD (low pressure chemical vapor deposition);

[0188] Step S750: growing a polysilicon layer using LPCVD;

[0189] Step S750: Diffusion of phosphorus into the silicon wafer.

[0190] In some examples, after preparing the polysilicon layer in step S700 , the step further includes removing the front side wrap-around plating in step S760 .

[0191] It can be understood that the front-side coating includes the silicon oxide layer generated on the front side of the silicon wafer in step S500, and the tunnel oxide layer and polysilicon layer materials coated on the front side when the tunnel oxide layer and polysilicon layer are prepared on the back side.

[0192] Step S800: a passivation layer and an anti-reflection layer are sequentially prepared on both surfaces of the silicon wafer.

[0193] It can be understood that step S800 includes sequentially preparing a passivation layer and an anti-reflection layer on the front side of the silicon wafer, and sequentially preparing a passivation layer and an anti-reflection layer on the back side of the silicon wafer.

[0194] Step S900: preparing a metal electrode in the metal contact area of ​​the silicon wafer.

[0195] In some examples, in step S900 , a front metal electrode is prepared on the front side of the silicon wafer, and a back metal electrode is prepared on the back side of the silicon wafer.

[0196] In some of the examples, in the battery preparation method, the step of preparing the metal electrode includes: applying a metal conductive paste to the metal contact area of ​​the silicon wafer, and then performing LECO laser-assisted sintering.

[0197] The metal conductive paste is an instantaneous current under the action of LECO. In the LECO process, the metal conductive paste will form an alloy of silicon and metal with the first part (spike structure) of the pyramid-like structure (for example, when the metal conductive paste is silver paste, a silicon-silver alloy is formed). The generated alloy has less damage to the battery passivation and is conducive to transmission; and the first part (spike structure) of the above-mentioned crystalline silicon velvet structure can provide contact points that are easier to transmit LECO current, thereby effectively improving the photoelectric conversion efficiency.

[0198] It can be understood that L1, α and h1 / h2 in the pyramid-like structure affect the volume of LECO action. On the basis of controlling d and keeping L1, α and h1 / h2 within the above range, the larger the volume of the first part in the pyramid-like structure is, the larger the volume of the silicon-silver alloy formed is, and the more significant the improvement in photoelectric conversion efficiency is.

[0199] One embodiment of the present application provides a photovoltaic module, including the above-mentioned battery or a battery produced by the above-mentioned battery production method.

[0200] It can be understood that photovoltaic modules can be used in photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be used in equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. It can also be understood that the application scenarios of photovoltaic systems include but are not limited to this, that is, photovoltaic systems can be used in all fields that require solar energy to generate electricity. 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 can be an array combination of multiple photovoltaic modules. For example, multiple photovoltaic modules can 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 to be converted into the alternating current required by the mains power grid and then connected to the mains power network to achieve solar power supply.

[0201] The present application will be described in further detail below in conjunction with specific implementation methods, but the implementation methods of the present application are not limited thereto.

[0202] Example 1

[0203] (1) Performing a first texturing treatment and a second texturing treatment on both surfaces of the silicon wafer in sequence;

[0204] The texturing agent used in the first texturing treatment includes the following components, calculated by mass percentage: 0.3% 2-methyl-2,4-pentanediol, 1.5% sodium carboxymethyl cellulose, 0.22% 5-nitroguaiacol, 0.2% triclosan, 0.3% sodium hydroxide, 0.2% sodium acetate, 0.2% sodium chloride, and the balance water; the temperature of the first texturing treatment is 80°C;

[0205] The texturing agent used in the second texturing treatment includes the following components, calculated by mass percentage: 0.3% 2-methyl-2,4-pentanediol, 1.5% sodium carboxymethyl cellulose, 0.22% 5-nitroguaiacol, 0.2% triclosan, 0.3% sodium hydroxide, 0.1% sodium poly[(naphthaldehyde) sulfonate], 0.7% sodium lignin sulfonate, 0.3% benzotriazole, 0.15% sodium acetate, 0.2% sodium chloride, and the balance water; the temperature of the second texturing treatment is 70°C, and the time is 80 seconds;

[0206] The pyramid-like structure formed is as follows Figure 3 As shown, the maximum value d of the distance from a point on the side surface of the tower top (first part) to the corresponding extension surface of the side surface of the tower bottom (second part) is 100 nm;

[0207] (2) Using a semiconductor source to diffuse silicon wafers;

[0208] (3) Laser mold opening of the non-metallic contact area on the front side of the silicon wafer;

[0209] (4) The non-metallic contact area after laser mold opening is subjected to a third texturing treatment. The texturing agent used in the third texturing treatment is the same as the texturing agent used in the second texturing treatment in step (1). The temperature of the third texturing treatment is 65°C. In the silicon substrate formed, δ1-δ2=0.5 μm;

[0210] (5) Double-sided oxidation treatment of silicon wafers;

[0211] (6) Back polishing of silicon wafer;

[0212] (7) Sequentially preparing a tunnel oxide layer and a polysilicon layer on the back side of the silicon wafer;

[0213] (8) Remove the front side plating;

[0214] (9) Sequentially preparing a passivation layer and an anti-reflection layer on both surfaces of the silicon wafer;

[0215] (10) Prepare metal electrodes in the metal contact area of ​​the silicon wafer.

[0216] Example 2

[0217] The difference from Example 1 is that in step (4), the temperature of the third texturing treatment is 80° C., and δ1-δ2=11 μm.

[0218] Example 3

[0219] The difference from Example 1 is that step (3) and step (4) are omitted, and δ1=δ2.

[0220] Example 4

[0221] The difference from Example 1 is that in step (4), the texturing agent used in the third texturing treatment is the same as the texturing agent used in the first texturing treatment in step (1).

[0222] Example 5

[0223] The difference from Example 1 is that the time of the second texturing treatment in step (1) is 140s, and in the pyramid-like structure formed, the maximum value d of the distance from a point on the side of the top of the tower (first part) to the extended surface of the corresponding side of the bottom of the tower (second part) is 200nm.

[0224] Comparative Example 1

[0225] The difference from Example 1 is that the sodium lignin sulfonate in the texturing agent used in the second texturing treatment in step (1) is replaced with lignin sulfonic acid of equal mass content to make a standard pyramid, such as Figure 4 shown.

[0226] The reflectivity of the silicon substrate formed by the third texturing treatment in step (4) of Example 1 and Comparative Example 1 was tested. The reflectivity of Example 1 was 8.40%, and the reflectivity of Comparative Example 1 was 9.38%.

[0227] The open circuit voltage Voc, short circuit current density Isc, fill factor FF and energy conversion efficiency Eta of the batteries prepared in each embodiment and comparative example were tested using IV curves. The test conditions were: AM 1.5G standard solar spectrum, irradiance of 1000W / m 2 The experimental test results are detailed in Table 1.

[0228] Table 1

[0229]

[0230] As can be seen from Table 1, compared with Comparative Example 1, the photoelectric conversion efficiency of the batteries prepared in each embodiment is higher.

[0231] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0232] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A crystalline silicon textured structure, characterized in that: The crystalline silicon textured structure includes a silicon substrate and a pyramid-like structure arranged on the silicon substrate. The pyramid-like structure includes a first part and a second part. The first part is located on a side of the second part away from the silicon substrate. The first part has a first side surface, the first side surface is a concave structure, and the first part is a spike structure.

2. The crystalline silicon textured structure according to claim 1, wherein: The second portion has a second side surface connected to the first side surface. A maximum value of distances from a point on the first side surface to an extension surface of the second side surface is d, and 10 nm≤d≤200 nm.

3. The crystalline silicon textured structure according to claim 1, wherein: The crystalline silicon textured structure satisfies at least one of the following characteristics: (1) The distance between the endpoints of two adjacent side edges of the second portion away from the silicon substrate is L1, 50 nm ≤ L1 ≤ 200 nm; (2) The distance between the endpoints of two adjacent side edges in the second portion close to the silicon substrate is L2, 1000 nm≤L2≤3000 nm.

4. The crystalline silicon textured structure according to claim 3, wherein: An included angle α between at least one side edge of the second portion and the silicon substrate is 56°≤α≤68°.

5. The crystalline silicon textured structure according to any one of claims 1 to 4, wherein: Along the vertical direction of the silicon substrate, the height of the first portion is h1, the height of the second portion is h2, and the crystalline silicon textured structure meets at least one of the following characteristics: (1)10 nm≤h1≤1000 nm; (2) 500nm≤h2≤2000nm; (3) 0.02≤h1 / h2≤1.

6. A method for preparing a crystalline silicon textured structure according to any one of claims 1 to 5, characterized in that: The following steps are involved: A first texturing treatment and a second texturing treatment are sequentially performed on at least one surface of the silicon wafer, wherein the texturing agent used in the second texturing treatment includes sodium lignin sulfonate and benzotriazole.

7. The method for preparing a crystalline silicon textured structure according to claim 6, wherein: The texturing agent includes the following components in parts by mass: 0.2-0.3 parts of 2-methyl-2,4-pentanediol, 1.5-2 parts of sodium carboxymethyl cellulose, 0.18-0.22 parts of 5-nitroguaiacol, 0.2-0.25 parts of triclosan, 0.3-0.5 parts of sodium hydroxide, 0.1-0.15 parts of poly[sodium naphthalene formaldehyde sulfonate], 0.2-0.7 parts of sodium lignin sulfonate, 0.1-0.3 parts of benzotriazole, 0.05-0.15 parts of sodium acetate, 0.2-0.4 parts of sodium chloride and 95-96.97 parts of water.

8. The method for preparing a crystalline silicon textured structure according to any one of claims 6 to 7, wherein: The method for preparing the crystalline silicon textured structure satisfies at least one of the following characteristics: (1) In the texturing agent, the mass fraction of the sodium lignin sulfonate is greater than the mass fraction of the benzotriazole; (2) In the texturing agent, the mass fraction of the sodium lignin sulfonate is 0.3 to 0.7 parts; (3) In the texturing agent, the mass fraction of the benzotriazole is 0.2 to 0.3 parts; (4) The temperature of the second texturing treatment is 68°C to 76°C, and the time is 80s to 160s.

9. A battery, characterized in that: It includes a silicon substrate and a metal electrode, at least one surface of the silicon substrate includes a metal contact area, the metal electrode is arranged in the metal contact area, and the metal contact area includes the crystalline silicon velvet structure as described in any one of claims 1 to 5 or the crystalline silicon velvet structure prepared by the preparation method of the crystalline silicon velvet structure as described in any one of claims 6 to 8.

10. The battery according to claim 9, wherein The surface of the silicon substrate further includes a non-metallic contact region, and the non-metallic contact region includes the crystalline silicon textured structure.

11. The battery according to claim 10, wherein The thickness of the silicon substrate in the metal contact area is δ1, and the thickness of the silicon substrate in the non-metal contact area is δ2, where δ1>δ2.

12. The battery according to claim 11, wherein δ1-δ2=0.5 μm~15 μm.

13. The battery according to any one of claims 10 to 12, wherein: The total area of ​​the non-metallic contact region is S1, and the total area of ​​the metal contact region is S2, where S1>S2.

14. The battery according to any one of claims 10 to 12, wherein: The silicon substrate is doped with boron group elements, the doping concentration of the boron group elements in the metal contact area is C1, and the doping concentration of the boron group elements in the non-metal contact area is C2, where C1>C2.

15. The battery according to claim 14, wherein The boron group elements are independently selected from at least one of boron, aluminum, gallium and indium.

16. The battery according to any one of claims 9 to 12, wherein: The silicon substrate includes a front side and a back side, and the battery satisfies at least one of the following characteristics: (1) The battery comprises a tunneling oxide layer and a polysilicon layer, wherein the tunneling oxide layer is provided on the back side of the silicon substrate, and the polysilicon layer is provided on a side of the tunneling oxide layer away from the silicon substrate; (2) The cell includes a passivation layer and an anti-reflection layer, wherein the passivation layer is arranged on the front surface of the silicon substrate, and the anti-reflection layer is arranged on the side of the passivation layer away from the silicon substrate.

17. A method for preparing a battery according to any one of claims 9 to 16, characterized in that: The following steps are involved: Providing a silicon wafer, wherein at least one surface of the silicon wafer comprises a metal contact area; performing a first texturing treatment and a second texturing treatment in sequence on the metal contact area of ​​the silicon wafer; the texturing agent used in the second texturing treatment includes sodium lignin sulfonate and benzotriazole; A metal electrode is prepared in the metal contact area.

18. The method for preparing a battery according to claim 17, wherein: The following steps are involved: Performing a first texturing treatment and a second texturing treatment on both surfaces of the silicon wafer in sequence; performing diffusion processing on the silicon wafer using a semiconductor source; Laser molding the non-metallic contact area on the front side of the silicon wafer; Performing a third texturing treatment on the non-metallic contact area after the laser mold opening; performing double-sided oxidation treatment on the silicon wafer; performing back polishing on the silicon wafer; sequentially preparing a tunnel oxide layer and a polysilicon layer on the back side of the silicon wafer; Sequentially preparing a passivation layer and an anti-reflection layer on both surfaces of the silicon wafer; A metal electrode is prepared in the metal contact area of ​​the silicon wafer.

19. The method for preparing a battery according to any one of claims 17 to 18, wherein: The steps of preparing the metal electrode include: placing a metal conductive paste on the metal contact area of ​​the silicon wafer, and then performing LECO laser-assisted sintering.

20. A photovoltaic module, characterized in that: A battery comprising the battery according to any one of claims 9 to 16 or a battery prepared by the method for preparing the battery according to any one of claims 17 to 19.

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