Solar cell and method of manufacturing the same, photovoltaic module, and photovoltaic system

Abstract

The application relates to the technical field of solar cells, in particular to a solar cell, a preparation method thereof, a photovoltaic module and a photovoltaic system. The application aims to improve the welding firmness of the electroplated conductive metal and the transparent conductive oxide layer. A preparation method of a solar cell comprises the following steps: providing a substrate layer, a first surface of the substrate layer is sequentially stacked with a first transparent conductive oxide layer and a first conductive pattern; forming a first dielectric layer on the side of the first conductive pattern away from the substrate layer, the first dielectric layer covers at least a part of the surface of a first porous structure of the first conductive pattern in a first region and exposes at least a part of the surface of the first porous structure; forming a first conductive metal layer on the side of the first dielectric layer away from the substrate layer and in a second region, the first conductive metal layer is filled in the first porous structure of the first conductive pattern and is in contact with at least a part of the surface of the first porous structure of the first conductive pattern, thereby forming a first grid line pattern; and removing the part of the first dielectric layer on the first region.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a solar cell and its preparation method, a photovoltaic module and a photovoltaic system. Background Technology

[0002] Hetero-junction (HJT) solar cells are made by depositing amorphous silicon thin films on crystalline silicon. They combine the advantages of crystalline silicon and thin-film solar cells, offering benefits such as high conversion efficiency, low processing temperature, high stability, low degradation rate, and bifacial power generation. Compared to PERC (Passivated Emitter and Rear Contact) cells, HJT solar cells have higher conversion efficiency. However, the high cost of equipment and materials used in manufacturing HJT solar cells has limited their large-scale application.

[0003] As the final step in manufacturing HJT solar cells—creating the grid pattern—the commonly used process involves screen printing using silver paste. However, this method is extremely costly, with the low-temperature silver paste accounting for 40% of the non-silicon cost of HJT solar cell manufacturing. Therefore, cost reduction is urgently needed. Currently, electroplating technology is the most promising alternative to silver paste screen printing, enabling cost reduction and efficiency improvement for HJT solar cells. However, due to the poor adhesion between the electroplated conductive metal layer and the transparent conductive oxide layer in HJT solar cells, peeling is prone to occur. Therefore, applying electroplating technology to the metallization process of HJT solar cells still presents significant technical challenges. Summary of the Invention

[0004] Therefore, it is necessary to provide a solar cell and its fabrication method, a photovoltaic module, and a photovoltaic system to improve the welding strength of the electroplated conductive metal and transparent conductive oxide layers.

[0005] In a first aspect, a method for preparing a solar cell is provided, comprising:

[0006] A substrate layer is provided, the substrate layer including a first surface and a second surface disposed opposite to each other along its thickness direction, the first surface having a first transparent conductive oxide layer and a first conductive pattern sequentially stacked, the first conductive pattern being in contact with the first transparent conductive oxide layer, the first conductive pattern having a first porous structure;

[0007] A first dielectric layer is formed on the side of the first conductive pattern away from the substrate layer, the first dielectric layer at least covering a first region, while exposing at least a portion of the surface of the first porous structure of the first conductive pattern; wherein, the first region is the area of ​​the first transparent conductive oxide layer not covered by the first conductive pattern.

[0008] A first conductive metal layer is formed on the side of the first dielectric layer away from the substrate layer and in a second region, the second region being the region where the first conductive pattern is located. The first conductive metal layer fills the first porous structure of the first conductive pattern and contacts at least a portion of the exposed surface of the first porous structure of the first conductive pattern to jointly form a first gate line pattern.

[0009] Remove the portion of the first dielectric layer located on the first region.

[0010] Optionally, the first conductive pattern is prepared by sintering a first conductive paste;

[0011] The metal particles in the first conductive paste have a particle size of 0.1 μm to 5 μm, so as to form the first porous structure on the first conductive pattern.

[0012] Optionally, the thickness of the first conductive pattern is 0.1 μm to 20 μm.

[0013] Optionally, the metal particles in the first conductive pattern include one or more of gold, silver, copper, nickel, and cobalt.

[0014] Optionally, the surface roughness of the first conductive pattern is 0.1 μm to 1 μm.

[0015] Optionally, the material of the first dielectric layer includes one or more of fluorides, oxides, and nitrides.

[0016] Optionally, the thickness of the first dielectric layer is 10 nm to 100 nm.

[0017] Optionally, the porosity of the first conductive pattern is less than 30%;

[0018] The formation of a first dielectric layer on the side of the first conductive pattern away from the substrate layer includes:

[0019] The first dielectric film is formed by deposition on the side of the first conductive pattern away from the substrate layer, and the first dielectric film continuously covers the first transparent conductive oxide layer and the first conductive pattern.

[0020] An opening is made in the portion of the first dielectric film located on the first conductive pattern to expose at least a portion of the surface of the first porous structure of the first conductive pattern.

[0021] Optionally, the step of creating an opening in the portion of the first dielectric film located on the first conductive pattern includes:

[0022] An opening is made in the portion of the first dielectric film located on the first conductive pattern using at least one of laser ablation, chemical etching, or physical polishing.

[0023] Optionally, the porosity of the first conductive pattern is 30% to 60%;

[0024] The formation of a first dielectric layer on the side of the first conductive pattern away from the substrate layer includes:

[0025] By deposition, the first dielectric layer is formed on the side of the first conductive pattern away from the substrate layer. The first dielectric layer continuously covers the first transparent conductive oxide layer, but only covers the first portion of the surface of the first porous structure of the first conductive pattern, exposing the remaining surfaces of the first porous structure other than the first portion of the surface.

[0026] Optionally, forming a first conductive metal layer on the side of the first dielectric layer away from the substrate layer and in the second region includes:

[0027] The first conductive metal layer is formed on the side of the first dielectric layer away from the substrate layer and in the second region by electroplating.

[0028] Optionally, the material of the first conductive metal layer includes one or a combination of copper and silver.

[0029] Optionally, the thickness of the first conductive metal layer is 1 μm to 100 μm.

[0030] Optionally, removing the portion of the first dielectric layer located on the first region includes:

[0031] The portion of the first dielectric layer located in the first region is removed by laser etching or chemical etching.

[0032] Optionally, the solar cell further includes: a second transparent conductive oxide layer and a second conductive pattern sequentially stacked on the second surface, the second conductive pattern and the second transparent conductive oxide layer being in contact, and the second conductive pattern having a second porous structure; the fabrication method further includes:

[0033] A second dielectric layer is formed on the side of the second conductive pattern away from the substrate layer, the second dielectric layer at least covering a third region, while exposing at least a portion of the surface of the second porous structure of the second conductive pattern; wherein, the third region is the area of ​​the second transparent conductive oxide layer not covered by the second conductive pattern;

[0034] A second conductive metal layer is formed on the side of the second dielectric layer away from the substrate layer and in a fourth region, the fourth region being the region where the second conductive pattern is located. The second conductive metal layer fills the second porous structure of the second conductive pattern and contacts at least a portion of the exposed surface of the second porous structure of the second conductive pattern to jointly form a second gate line pattern.

[0035] The portion of the second dielectric layer located on the third region is removed.

[0036] In a second aspect, a solar cell is provided, which is prepared using the preparation method described in the first aspect.

[0037] Thirdly, a photovoltaic module is provided, comprising: a plurality of solar cells connected in series and / or in parallel;

[0038] At least one of the solar cells is a solar cell as described in the second aspect.

[0039] Fourthly, a photovoltaic system is provided, comprising: a photovoltaic module as described in the third aspect.

[0040] By forming a first conductive pattern with a first porous structure on a first transparent conductive oxide layer, and forming a first dielectric layer in at least a first region, when a first conductive metal layer is subsequently formed by electroplating, the first conductive metal layer can fill the first porous structure of the first conductive pattern and contact at least a portion of the surface of the first porous structure, thereby forming a first grid pattern together with the first conductive pattern. This improves the bonding strength between the first conductive metal layer and the first conductive pattern, and prevents metal deposition in the first region, thus avoiding any impact on the light transmittance of the solar cell. This solves the problems in related technologies where the conductive metal layer is easily detached during electroplating deposition, and where the light transmittance of the transparent conductive oxide layer is reduced. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 A schematic flowchart illustrating a method for fabricating a solar cell according to an embodiment of this application;

[0043] Figure 2 A schematic flowchart illustrating another method for fabricating a solar cell provided in this application embodiment;

[0044] Figure 3 A schematic flowchart illustrating another method for fabricating a solar cell provided in this application embodiment;

[0045] Figure 4 This is a schematic flowchart illustrating another method for fabricating a solar cell provided in an embodiment of this application. Detailed Implementation

[0046] To facilitate understanding of this application, a more complete description is provided below. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0048] the term:

[0049] As used herein, the term "and / or" encompasses any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" includes three parallel options: A, B, and "a combination of A and B".

[0050] In this document, unless otherwise stated, "one or more" means any one of the listed items or any combination of the listed items. Similarly, "one or more" and other instances of "one or more" are to be understood in the same way unless otherwise stated.

[0051] In this document, terms such as "further," "even further," "especially," "for example," "as," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later. However, they should not be construed as limitations on the preceding technical solution or on the scope of protection of this document. Unless otherwise specified, A (as in B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0052] In this document, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0053] In this document, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. Furthermore, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood as not constituting a closed limitation on quantity. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0055] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0056] In this document, when referring to numerical intervals (i.e., numerical ranges), unless otherwise specified, the distribution of selectable values ​​within a numerical interval is considered continuous, and includes the two endpoints (i.e., the minimum and maximum values) of the numerical interval, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that 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 features or characteristics, these numerical ranges can be merged. 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 this numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, and other numerical interval types.

[0057] In this document, for methods involving multiple steps, unless otherwise explicitly stated herein, there is no strict order constraint on the execution of these steps; they may be executed in any order other than those described. Moreover, any step may include multiple sub-steps or multiple stages, which are not necessarily completed at the same time, but may be executed at different times, and their execution order is not necessarily sequential, but may be executed in turn, alternately, or simultaneously with other steps or parts of the sub-steps or stages of other steps.

[0058] The fill factor (FF) used in this paper refers to the ratio of the actual maximum obtainable power (Pm or Vmp*Jmp) to the theoretical (not actually obtainable) power (Jsc*Voc). Therefore, FF can be determined by the following formula:

[0059] FF = (Vmp * Jmp) / (Jsc * Voc)

[0060] Where Jmp and Vmp represent the current density and voltage at the maximum power point (Pm), respectively, this point is obtained by changing the resistance in the circuit until J*V reaches its maximum value; Jsc and Voc represent the short-circuit current and open-circuit voltage, respectively. The fill factor is a key parameter for evaluating solar cells. Commercial solar cells typically have a fill factor of approximately 60% or higher.

[0061] The open-circuit voltage (Voc) used in this paper is the potential difference between the anode and cathode of the device under conditions of no external load connection.

[0062] The power conversion efficiency (PCE) of solar cells used in this article refers to the percentage of power converted from absorbed light into electrical energy. The PCE of a solar cell can be measured under standard test conditions (STC) based on incident light irradiance (E: W / m²).2 ) and the surface area of ​​solar cells (Ac:m 2 The STC is calculated by dividing by the point of maximum power (Pm). STC typically refers to the value at a temperature of 25°C and an irradiance of 1000 W / m². 2 The spectrum of air quality 1.5 (AM1.5).

[0063] Currently, the laboratory efficiency of HJT solar cells has reached over 26%. Compared to PERC cells, HJT solar cells have higher conversion efficiency; however, the high cost of equipment and materials used in manufacturing HJT solar cells restricts their large-scale application.

[0064] The final step in manufacturing HJT solar cells—creating the grid pattern—currently uses silver paste as a raw material and employs screen printing. However, this method is extremely costly, with the low-temperature silver paste accounting for 40% of the non-silicon cost of HJT solar cell manufacturing. Therefore, cost reduction is urgently needed. Currently, electroplating technology shows the best potential to replace silver paste screen printing, achieving cost reduction and efficiency improvement for HJT solar cells.

[0065] However, due to the poor adhesion between the electroplated conductive metal layer and the transparent conductive oxide layer in HJT solar cells, they are prone to peeling off. Therefore, there are still significant technical challenges in applying electroplating technology to the metallization process of HJT solar cells.

[0066] In related technologies, the most common method to overcome this difficulty is to form an electroplating seed layer on the surface of the transparent conductive oxide layer, and then deposit a conductive metal layer on the electroplating seed layer by electroplating. However, the electroplating seed layer prepared in this way covers the transparent conductive oxide layer, which will reduce the light transmittance of the transparent conductive oxide layer.

[0067] Based on the above technical problems, firstly, some embodiments of this application provide a method for preparing a solar cell, such as... Figure 1 and Figure 2 As shown, it includes the following steps S11) to S14):

[0068] S11) A substrate layer 11 is provided, the substrate layer 11 including a first surface 11a and a second surface 11b disposed opposite to each other along its thickness direction. A first transparent conductive oxide layer 121 and a first conductive pattern 131 are sequentially stacked on the first surface 11a. The first conductive pattern 131 is in contact with the first transparent conductive oxide layer 121. The first conductive pattern 131 has a first porous structure.

[0069] The substrate 11 can be an N-type silicon substrate or a P-type silicon substrate, without specific limitations. The first surface 11a can be a front or a back surface. When the first surface 11a is the front surface, the second surface 11b is the back surface, and when the first surface 11a is the back surface, the second surface 11b is the front surface, without specific limitations.

[0070] In the following embodiments, the method for fabricating the solar cell will be described in detail, taking the substrate 11 as an N-type silicon substrate and the first surface 11a as the front side of the N-type silicon substrate.

[0071] The aforementioned first transparent conductive oxide layer 121 may include one or more of the following stacked structures: a fluorine-doped tin oxide (FTO) layer, an indium tin oxide (ITO) layer, a polyethylene naphthalene-2,6-dicarboxylate (PEN) polymer layer plated with ITO or FTO (ITO / PEN, FTO / PEN), and a polyethylene terephthalate (PET) polymer layer plated with ITO or FTO (ITO / PET, FTO / PET).

[0072] The thickness of the first transparent conductive oxide layer 121 is not limited. Optionally, the thickness of the first transparent conductive oxide layer 121 can be 60 nm to 80 nm.

[0073] The first conductive pattern 131 has a first porous structure, meaning that the surface roughness of the first conductive pattern 131 is greater than the surface roughness of the first transparent conductive oxide layer 121.

[0074] The first conductive pattern 131 can be prepared by sintering a first conductive paste. The first conductive paste may contain metal particles and glass powder, etc., thereby forming a first porous structure in the first conductive pattern 131 by sintering the first conductive paste.

[0075] For example, at least one of screen printing, laser transfer printing and inkjet printing can be used to form a first conductive paste with a first pattern on the surface of the first transparent conductive oxide layer 121 away from the substrate layer 11, and then sintered to prepare the first conductive pattern 131; wherein the shape of the first pattern can be the same as the shape of the first conductive pattern 131.

[0076] In some embodiments, the particle size of the metal particles in the first conductive paste can be 0.1 μm to 5 μm, so as to form a first porous structure on the first conductive pattern 131.

[0077] In these embodiments, the porosity of the first porous structure of the first conductive pattern 131 can be controlled by adjusting the particle size of the metal particles, thereby giving the first conductive pattern 131 a certain surface roughness, and thus obtaining a first conductive pattern 131 with a certain surface roughness and porosity.

[0078] In some embodiments, the surface roughness of the first conductive pattern 131 is 0.1 μm to 1 μm.

[0079] In some embodiments, the metal particles in the first conductive pattern 131 may include one or more of gold, silver, copper, nickel, and cobalt. By selecting the above-mentioned metal particles, the formed first conductive pattern 131 can have good electrical contact performance, and the surface pull-out force is increased, making it less prone to grid breakage.

[0080] The thickness of the first conductive pattern 131 is not specifically limited, as long as it can form a first conductive pattern 131 with a first porous structure. This allows the conductive metal layer to fill the first porous structure when a conductive metal layer is formed by electroplating, thereby improving the bonding strength of the electroplating.

[0081] In some embodiments, the thickness of the first conductive pattern 131 can be 0.1 μm to 20 μm.

[0082] In these embodiments, the first conductive pattern 131 is thinner, which can reduce the amount of paste used and thus reduce costs.

[0083] (S12) A first dielectric layer 141 is formed on the side of the first conductive pattern 131 away from the substrate layer 11. The first dielectric layer 141 at least covers the first region S, while exposing at least a portion of the surface of the first porous structure. The first region S is the region of the first transparent conductive oxide layer 121 that is not covered by the first conductive pattern 131.

[0084] The first dielectric layer 141 can be transparent or opaque; no specific limitation is made here. Transparency means that it does not affect the transmission of most visible light, and has a high light transmittance.

[0085] The material of the first dielectric layer 141 may include one or more of fluorides, oxides and nitrides.

[0086] Furthermore, the conductivity of the first dielectric layer 141 can be 0.1% of the conductivity of the first conductive pattern 131.

[0087] In some embodiments, the fluoride may include one or more of MgF2, LeF2, and SrF2; the oxide may include SiO2. x and AlO xOne or more of the following; nitrides include SiN x .

[0088] In some embodiments, the thickness of the first dielectric layer 141 can be 10 nm to 100 nm.

[0089] In these embodiments, the first dielectric layer 141 prepared from these materials can be transparent, which can significantly reduce the impact on the light transmittance of the solar cell. Moreover, since the material of the first dielectric layer 141 is different from that of the first transparent conductive oxide layer 121, the first dielectric layer 141 located on the first transparent conductive oxide layer 121 can be removed after the grid pattern is prepared without affecting the light transmittance of the solar cell.

[0090] S13) A first conductive metal layer 151 is formed on the side of the first dielectric layer 141 away from the substrate layer 11 and in the second region N. The second region N is the region where the first conductive pattern 131 is located. The first conductive metal layer 151 fills the first porous structure of the first conductive pattern 131 and contacts at least a portion of the exposed surface of the first porous structure of the first conductive pattern 131 to jointly form the first gate line pattern L1.

[0091] Wherein, a first conductive metal layer 151 is formed on the side of the first dielectric layer 141 away from the substrate layer 11 and in the second region N, it may include:

[0092] An electroplating method is used to form a first conductive metal layer 151 on the side of the first dielectric layer 141 away from the substrate layer 11 and in the second region N.

[0093] In some embodiments, the material of the first conductive metal layer 151 may include one or more of copper and silver. For example, the material of the first conductive metal layer 151 may be copper, silver, a mixture of copper and silver, or a copper-silver alloy.

[0094] In some embodiments, the thickness of the first conductive metal layer 151 can be 1 μm to 100 μm.

[0095] S14) Remove the portion of the first dielectric layer 141 located on the first region S.

[0096] In some embodiments, laser etching or chemical etching can be used to remove a portion of the first dielectric layer 141 located in the first region S.

[0097] In the solar cell fabrication method provided in this application embodiment, a first conductive pattern 131 with a first porous structure is formed on a first transparent conductive oxide layer 121, and a first dielectric layer 141 is formed at least in a first region S. When a first conductive metal layer 151 is subsequently formed by electroplating, the first conductive metal layer 151 can fill the first porous structure of the first conductive pattern and contact at least a portion of the surface of the first porous structure, thereby forming a first grid pattern L1 together with the first conductive pattern 131. This improves the bonding strength between the first conductive metal layer 151 and the first conductive pattern 131; furthermore, it prevents metal deposition in the first region S, thus avoiding any impact on the light transmittance of the solar cell. This solves the problems in related technologies where the conductive metal layer is easily detached during electroplating deposition, and where the light transmittance of the transparent conductive oxide layer is reduced.

[0098] Meanwhile, the first conductive pattern 131 can be made thinner, which can reduce the amount of the first conductive paste used. The conductivity of the first gate pattern L1 can be improved by electroplating the first conductive metal layer 151 and making the first conductive metal layer 151 and the first conductive pattern 131 in close contact.

[0099] The method of forming the first dielectric layer 141 is not specifically limited. The first dielectric layer 141 can be formed only in the first region S by using a mask to block it, or it can be formed in the first region S by depositing the entire layer and opening holes, thus exposing at least part of the surface of the first porous structure.

[0100] In some embodiments, such as Figure 1 As shown, the porosity of the first conductive pattern 131 is less than 30%; S12), a first dielectric layer 141 is formed on the side of the first conductive pattern 131 away from the substrate layer 11, as shown. Figure 1 As shown, it includes:

[0101] S121) By deposition, a first dielectric film 100 is formed on the side of the first conductive pattern 131 away from the substrate layer 11, and the first dielectric film 100 continuously covers the first transparent conductive oxide layer 121 and the first conductive pattern 131.

[0102] (S122) An opening is made in the portion of the first dielectric film 100 located on the first conductive pattern 131 to expose at least a portion of the surface of the first porous structure of the first conductive pattern 131.

[0103] In these embodiments, because the porosity of the first conductive pattern 131 is low, when the first dielectric layer 141 is formed by deposition, the first dielectric layer 141 continuously covers the first transparent conductive oxide layer 121 and the first conductive pattern 131. This can be referred to as the first dielectric film 100. The first dielectric layer 141 can be prepared by creating openings in the portion of the first dielectric film 100 located on the first conductive pattern 131, thus exposing at least a portion of the surface of the first porous structure of the first conductive pattern 131. Furthermore, creating openings in the portion of the first dielectric film 100 located on the first conductive pattern 131 can increase the uniformity of the pore distribution in the first porous structure, avoiding excessive or insufficient openings in the first dielectric layer 141, and improving the continuity and uniformity of the subsequently electroplated first conductive metal layer 151.

[0104] In some embodiments, openings are made in the portion of the first dielectric film 100 located on the first conductive pattern 131, including:

[0105] An opening is made in the portion of the first dielectric film 100 located on the first conductive pattern 131 by at least one of laser ablation, chemical etching or physical polishing.

[0106] In other embodiments, the porosity of the first conductive pattern 131 is 30% to 60%; S12), a first dielectric layer 141 is formed on the side of the first conductive pattern 131 away from the substrate layer 11, such as... Figure 2 As shown, it includes:

[0107] (S121) By deposition, a first dielectric layer 141 is formed on the side of the first conductive pattern 131 away from the substrate layer 11. The first dielectric layer 141 continuously covers the first transparent conductive oxide layer 121, but only covers the first part of the surface of the first porous structure of the first conductive pattern 131, exposing the remaining surfaces of the first porous structure of the first conductive pattern 131 other than the first part of the surface.

[0108] In these embodiments, because the first conductive pattern 131 has a high porosity, when the first dielectric layer 141 is formed by deposition, since the surface of the first transparent conductive oxide layer 121 is relatively smooth, the first dielectric layer 141 will continuously cover the first transparent conductive oxide layer 121, and only cover the first part of the rough surface of the first conductive pattern 131, exposing the remaining surface of the first conductive pattern 131. At this time, the remaining surface of the first conductive pattern 131 can vary depending on the porosity of the first conductive pattern 131. For example, when the porosity of the first conductive pattern 131 is large, the area of ​​the remaining surface of the first conductive pattern 131 is large, and when the porosity of the first conductive pattern 131 is small, the area of ​​the remaining surface of the first conductive pattern 131 is small, thereby exposing at least a part of the surface of the first porous structure of the first conductive pattern 131.

[0109] In some embodiments, such as Figure 3 and Figure 4 As shown, the solar cell further includes: a second transparent conductive oxide layer 122 and a second conductive pattern 132 sequentially stacked on the second surface 11b, the second conductive pattern 132 and the second transparent conductive oxide layer 122 being in contact, and the second conductive pattern 132 having a second porous structure. Figure 3 and Figure 4 As shown, the preparation method further includes:

[0110] (S15) A second conductive pattern 132 is formed on the second transparent conductive oxide layer 122. The method for preparing the second conductive pattern 132 can refer to the method for preparing the first conductive pattern described above, and will not be repeated here.

[0111] S16) A second dielectric layer 142 is formed on the side of the second conductive pattern 132 away from the substrate layer 11. The second dielectric layer 142 at least covers the third region P, while exposing at least a portion of the surface of the second porous structure. The third region P is the region of the second transparent conductive oxide layer 122 that is not covered by the second conductive pattern 132.

[0112] S17) A second conductive metal layer 152 is formed on the side of the second dielectric layer 142 away from the base layer 11 and in the fourth region R. The fourth region R is the region where the second conductive pattern 132 is located. The second conductive metal layer 152 fills the second porous structure of the second conductive pattern 132 and contacts at least part of the exposed surface of the second porous structure to jointly form the second gate line pattern L2.

[0113] S18) Remove the portion of the second dielectric layer 142 located on the third region P.

[0114] In these embodiments, similar to the first conductive pattern 131, first dielectric layer 141, and first conductive metal layer 151 described above, a second conductive pattern 132 with a second porous structure is formed on the second transparent conductive oxide layer 122, and a second dielectric layer 142 is formed at least in the third region P. When the second conductive metal layer 152 is subsequently formed by electroplating, the second conductive metal layer 152 can fill the second porous structure of the second conductive pattern 132 and contact at least a portion of the surface of the second porous structure, thereby forming the second grid pattern L2 together with the second conductive pattern 132. This improves the bonding strength between the second conductive metal layer 152 and the second conductive pattern 132; furthermore, it prevents metal deposition in the third region P, thus avoiding any impact on the light transmittance of the solar cell. This solves the problems in related technologies where the conductive metal layer is easily detached during electroplating deposition, and where the light transmittance of the transparent conductive oxide layer is reduced.

[0115] In some embodiments, the specific formation methods, materials, thicknesses of the second transparent conductive oxide layer 122, the second dielectric layer 142, and the second conductive metal layer 152, as well as the removal method of the second dielectric layer 142, can all refer to the above description of the first transparent conductive oxide layer 121, the first dielectric layer 141, and the first conductive metal layer 151, and will not be repeated here. Specific illustrations of the preparation methods can be found in the diagrams provided. Figure 3 and Figure 4 Unlike the first dielectric layer 141 which uses a hole in the first dielectric film 100, the second dielectric layer 142 can be obtained by using a hole in the second dielectric film 200.

[0116] Secondly, this application provides a solar cell prepared by the method described in the first aspect.

[0117] Thirdly, this application provides a photovoltaic module that includes the solar cell described in the second aspect.

[0118] Fourthly, this application provides a photovoltaic system comprising the photovoltaic modules described in the third aspect.

[0119] The present application will be further described in detail below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0120] In the specific embodiments described below, the measurement parameters involving raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision.

[0121] Example 1

[0122] The method for preparing the solar cell provided in Example 1 is as follows:

[0123] Step 1) Provide a solar cell with an indium tin oxide (ITO) thin film;

[0124] Step 2) Using a screen printing process, silver paste is coated onto the front side of the battery cell from Step 1) and onto indium tin oxide to form a first conductive paste with a first pattern. This is then sintered to form a first conductive pattern with a first porous structure. The surface roughness of the first conductive pattern is 0.1 μm, its thickness is 10 μm, and its porosity is 5%. The silver paste contains silver particles with a diameter of 0.1 μm.

[0125] Step 3) Deposit a first dielectric film with a thickness of 10 nm on the surface of the solar cell with the first conductive pattern formed in Step 2) using a physical vapor deposition process; wherein the material of the first dielectric film is SiO2. x ;

[0126] Step 4) Use a laser to open the first dielectric film in step 3) so that it forms an opening on the first conductive pattern, exposing the first porous structure on the first conductive pattern.

[0127] Step 5) A first conductive metal layer with a thickness of 20 μm is formed at the first conductive pattern formed in step 4). The first conductive metal layer can be a copper-silver electroplated metal layer.

[0128] Step 6) Clean the battery cell obtained in step 5) with hydrofluoric acid solution to remove the first dielectric layer on the first transparent conductive oxide layer;

[0129] Step 7) Form a second conductive pattern, a second dielectric layer and a second conductive metal layer sequentially on the back of the battery cell. The specific preparation method can be referred to the first conductive pattern, the first dielectric layer and the first conductive metal layer above, and will not be repeated here.

[0130] Example 2

[0131] The method for preparing the solar cell provided in Example 2 is basically the same as that for preparing the solar cell provided in Example 1, except that:

[0132] In step 2), the porosity of the first conductive pattern is 30% and the thickness is 10 μm. The silver particles in the silver paste have a particle size of 1 μm.

[0133] In steps 3) and 4), a first dielectric layer with a thickness of 10 nm is formed directly using physical vapor deposition in step 2). The first dielectric layer exposes part of the surface of the first porous structure on the first conductive pattern.

[0134] Example 3

[0135] The method for preparing the solar cell provided in Example 3 is basically the same as that for preparing the solar cell provided in Example 1, except that:

[0136] In step 2), the porosity of the first conductive pattern is 50% and the thickness is 10 μm. The silver particles in the silver paste have a particle size of 3 μm.

[0137] In steps 3) and 4), a first dielectric layer with a thickness of 10 nm is formed directly using physical vapor deposition in step 2). The first dielectric layer exposes part of the surface of the first porous structure on the first conductive pattern.

[0138] Example 4

[0139] The method for preparing the solar cell provided in Example 4 is basically the same as that for preparing the solar cell provided in Example 1, except that:

[0140] In step 2), the porosity of the first conductive pattern is 60% and the thickness is 10 μm. The silver particles in the silver paste have a particle size of 5 μm.

[0141] In steps 3) and 4), a first dielectric layer with a thickness of 10 nm is formed directly using physical vapor deposition in step 2). The first dielectric layer exposes part of the surface of the first porous structure on the first conductive pattern.

[0142] Comparative Example 1

[0143] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that:

[0144] The first conductive metal layer is formed by electroplating directly onto the first transparent conductive oxide layer.

[0145] The solar cells prepared in Example 1, Example 2 and Comparative Example 1 were subjected to relevant performance tests, and the test results are shown in Table 1 below.

[0146] Table 1

[0147] Example 1 8.65 0.739 78.87 22.88 84.46 Example 2 8.63 0.738 79.15 22.87 82.47 Example 3 8.64 0.739 79.23 22.94 82.35 Example 4 8.63 0.737 79.03 22.82 82.93 Comparative Example 1 8.62 0.736 78.81 22.67 82.32

[0148] pFF represents the pseudo-Fill Factor excluding the influence of Rs, where Rs represents the series resistance of the battery.

[0149] As shown in Table 1, the solar cells provided in this application embodiment have significantly improved cell efficiency (PCE), fill factor, open-circuit voltage, and short-circuit current. This indicates that the preparation method of the solar cells provided in this application embodiment achieves the goal of improving the light transmittance and conductivity of the solar cells, and can significantly improve the photoelectric performance of the solar cells.

[0150] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above 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.

[0151] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification can be used to interpret the scope of the claims.

Claims

1. A method for preparing a solar cell, characterized in that, include: A substrate layer is provided, the substrate layer including a first surface and a second surface disposed opposite to each other along its thickness direction, a first transparent conductive oxide layer and a first conductive pattern being sequentially stacked on the first surface, the first conductive pattern being in contact with the first transparent conductive oxide layer, and the first conductive pattern having a first porous structure. A first dielectric layer is formed on the side of the first conductive pattern away from the substrate layer, the first dielectric layer at least covering a first region, while exposing at least a portion of the surface of the first porous structure of the first conductive pattern; wherein, the first region is the area of ​​the first transparent conductive oxide layer not covered by the first conductive pattern. A first conductive metal layer is formed on the side of the first dielectric layer away from the substrate layer and in a second region, the second region being the region where the first conductive pattern is located. The first conductive metal layer fills the first porous structure of the first conductive pattern and contacts at least a portion of the exposed surface of the first porous structure of the first conductive pattern to jointly form a first gate line pattern. Remove the portion of the first dielectric layer located on the first region.

2. The preparation method according to claim 1, characterized in that, The first conductive pattern is prepared by sintering a first conductive paste; The metal particles in the first conductive paste have a particle size of 0.1 μm to 5 μm, so as to form the first porous structure on the first conductive pattern.

3. The preparation method according to claim 1, characterized in that, The thickness of the first conductive pattern is 0.1 μm to 20 μm.

4. The preparation method according to claim 1, characterized in that, The metal particles in the first conductive pattern include one or more of gold, silver, copper, nickel, and cobalt.

5. The preparation method according to claim 1, characterized in that, The surface roughness of the first conductive pattern is 0.1 μm to 1 μm.

6. The preparation method according to claim 1, characterized in that, The material of the first dielectric layer includes one or more of fluorides, oxides, and nitrides.

7. The preparation method according to claim 1, characterized in that, The thickness of the first dielectric layer is 10nm~100nm.

8. The preparation method according to any one of claims 1 to 7, characterized in that, The porosity of the first conductive pattern is less than 30%; The formation of a first dielectric layer on the side of the first conductive pattern away from the substrate layer includes: A first dielectric film is formed by deposition on the side of the first conductive pattern away from the substrate layer, and the first dielectric film continuously covers the first transparent conductive oxide layer and the first conductive pattern. An opening is made in the portion of the first dielectric film located on the first conductive pattern to expose at least a portion of the surface of the first porous structure of the first conductive pattern.

9. The preparation method according to claim 8, characterized in that, The step of creating an opening in the portion of the first dielectric film located on the first conductive pattern includes: An opening is made in the portion of the first dielectric film located on the first conductive pattern using at least one of laser ablation, chemical etching, or physical polishing.

10. The preparation method according to any one of claims 1 to 7, characterized in that, The porosity of the first conductive pattern is 30%~60%; The formation of a first dielectric layer on the side of the first conductive pattern away from the substrate layer includes: By deposition, the first dielectric layer is formed on the side of the first conductive pattern away from the substrate layer. The first dielectric layer continuously covers the first transparent conductive oxide layer, but only covers the first portion of the surface of the first porous structure of the first conductive pattern, exposing the remaining surfaces of the first porous structure other than the first portion of the surface.

11. The preparation method according to any one of claims 1 to 7, characterized in that, The formation of a first conductive metal layer on the side of the first dielectric layer away from the substrate layer and in the second region includes: The first conductive metal layer is formed on the side of the first dielectric layer away from the substrate layer and in the second region by electroplating.

12. The preparation method according to claim 11, characterized in that, The material of the first conductive metal layer includes one or a combination of copper and silver.

13. The preparation method according to claim 11, characterized in that, The thickness of the first conductive metal layer is 1μm to 100μm.

14. The preparation method according to any one of claims 1 to 7, characterized in that, Removing the portion of the first dielectric layer located in the first region includes: The portion of the first dielectric layer located in the first region is removed by laser etching or chemical etching.

15. The preparation method according to any one of claims 1 to 7, characterized in that, The solar cell further includes: a second transparent conductive oxide layer and a second conductive pattern sequentially stacked on the second surface, the second conductive pattern and the second transparent conductive oxide layer being in contact, and the second conductive pattern having a second porous structure; the fabrication method further includes: A second dielectric layer is formed on the side of the second conductive pattern away from the substrate layer, the second dielectric layer at least covering a third region, while exposing at least a portion of the surface of the second porous structure of the second conductive pattern; wherein, the third region is the area of ​​the second transparent conductive oxide layer not covered by the second conductive pattern; A second conductive metal layer is formed on the side of the second dielectric layer away from the substrate layer and in a fourth region, the fourth region being the region where the second conductive pattern is located. The second conductive metal layer fills the second porous structure of the second conductive pattern and contacts at least a portion of the exposed surface of the second porous structure of the second conductive pattern to jointly form a second gate line pattern. The portion of the second dielectric layer located on the third region is removed.

16. A solar cell, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 15.

17. A photovoltaic module, characterized in that, include: Multiple solar cells connected in series and / or in parallel; At least one of the solar cells is the solar cell as described in claim 16.

18. A photovoltaic system, characterized in that, include: The photovoltaic module as described in claim 17.

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