Back contact solar cell, method of manufacture, apparatus, stacked cell and module

Abstract

The embodiment of the present application relates to the photovoltaic field, and provides a back contact solar cell, a preparation method, equipment, a laminated cell and a module. The back contact solar cell comprises a substrate, the substrate has opposite first and second surfaces, the first surface comprises alternately arranged first and second regions; a first functional layer, a first passivation layer and a first electrode are located in the first region; a second functional layer, a second passivation layer and a second electrode are located in the second region; the first functional layer comprises silicon oxynitride containing a first doping element, the second functional layer comprises silicon oxynitride containing a second doping element, the silicon oxynitride is an amorphous-nanocrystalline dual-phase structure, and the first doping element is different from the second doping element. The solar cell provided by the embodiment of the present application can at least reduce the process complexity of the preparation of the back contact solar cell.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a back-contact solar cell, a method for preparing a back-contact solar cell, equipment for preparing a back-contact solar cell, a tandem cell, and a photovoltaic module. Background Technology

[0002] Currently, N-type back-contact solar cells (N-TBCs) exhibit excellent photoelectric conversion efficiency due to the superior passivation of TOPCon and the unobstructed IBC structure. However, their back surface fabrication process is extremely complex: it requires multiple depositions of intrinsic polycrystalline silicon layers (≥3 times), two independent patterning processes (laser / photolithography), and multiple high-temperature doping and wet etching steps, totaling more than 15 steps. This fabrication process results in high equipment investment, low production capacity, and poor yield. Furthermore, multiple thermal cycles and acid washing damage the silicon surface, reducing passivation quality and limiting the improvement of open-circuit voltage.

[0003] Therefore, there is an urgent need for a back-contact solar cell that can overcome the above problems. Summary of the Invention

[0004] This application provides a back-contact solar cell, a method for preparing a back-contact solar cell, equipment for preparing a back-contact solar cell, a tandem cell, and a photovoltaic module, which at least helps to reduce the process complexity of preparing a back-contact solar cell.

[0005] According to some embodiments of this application, one aspect of this application provides a back-contact solar cell, comprising: a substrate having opposing first and second surfaces, the first surface including alternately arranged first and second regions; a first functional layer, a first passivation layer, and a first electrode located in the first region, the first passivation layer being located on the side of the first functional layer away from the substrate, and the first electrode being located on the side of the first functional layer away from the substrate and electrically connected to the first functional layer; a second functional layer, a second passivation layer, and a second electrode located in the second region, the second passivation layer being located on the side of the second functional layer away from the substrate, and the second electrode being located on the side of the second functional layer away from the substrate and electrically connected to the second functional layer; the first functional layer comprising silicon oxynitride containing a first dopant element, the second functional layer comprising silicon oxynitride containing a second dopant element, the silicon oxynitride being an amorphous-nanocrystalline dual-phase structure, and the first dopant element and the second dopant element being different.

[0006] In some embodiments, the thickness of the first functional layer is 150~200nm.

[0007] In some embodiments, the thickness of the second functional layer is 100~150nm.

[0008] In some embodiments, the back-contact solar cell satisfies at least one of the following: the first doping element is a group III element; the second doping element is a group V element.

[0009] In some embodiments, the back-contact solar cell satisfies at least one of the following: in the first functional layer, the doping concentration of the first dopant element is 2.3 × 10⁻⁶. 19 ~4.6×10 20 atoms / cm 3 In the second functional layer, the doping concentration of the second element is 2.3 × 10⁻⁶. 19 ~4.6×10 20 atoms / cm 3 .

[0010] In some embodiments, the distance between the first functional layer and the second surface is a first distance, the distance between the second functional layer and the second surface is a second distance, and the first distance is greater than the second distance.

[0011] According to some embodiments of this application, another aspect of this application provides a method for fabricating a back-contact solar cell, used to fabricate any of the aforementioned back-contact solar cells. The method for fabricating the back-contact solar cell includes: providing a substrate having opposing first and second surfaces, the first surface including alternately arranged first and second regions, forming a first material layer on the first surface; performing a first laser treatment on the first material layer located in the second region to obtain a second material layer, wherein the material of the first material layer includes silicon oxynitride containing doped elements, and the silicon oxynitride is an amorphous-nanocrystalline dual-phase structure; performing a diffusion treatment on the first material layer that has not undergone the first laser treatment to obtain a first functional layer; performing a second laser treatment on the second material layer to obtain a second functional layer, wherein the energy density of the second laser treatment is greater than the energy density of the first laser treatment; forming a first passivation layer and a first electrode on the side of the first functional layer away from the substrate; and forming a second passivation layer and a second electrode on the side of the second functional layer away from the substrate.

[0012] In some embodiments, forming a first material layer on the first surface includes: introducing a first gas into a cavity containing the substrate and applying a predetermined power, wherein the first gas includes a nitrogen source gas, an oxygen source gas, a silicon source gas, a doped source gas, and an inert gas, the temperature of the cavity is 380~420°C, the pressure of the cavity is 80~110Pa, and the predetermined power is 20~35W.

[0013] In some embodiments, performing a first laser treatment on the first material layer located in the second region to obtain a second material layer includes: scanning the first material layer with a first laser to obtain the second material layer, wherein the light source of the first laser is infrared light, the scanning speed of the first laser is 1 m / s to 10 m / s, and the energy density of the first laser is 0 to 0.5 J / cm². 2 The pulse width of the first laser is 10~100ns.

[0014] In some embodiments, the first material layer that has not undergone the first laser treatment is subjected to diffusion treatment to obtain a first functional layer, including: introducing a second gas into a cavity where the substrate is located and continuing for a predetermined time, wherein the temperature of the cavity is 800~900°C and the predetermined time is 10~20 min.

[0015] In some embodiments, the second material layer is subjected to a second laser treatment to obtain a second functional layer, comprising: scanning the second material layer with a second laser to obtain the second functional layer, wherein the light source of the second laser is green light or ultraviolet light, the scanning speed of the second laser is 0.5~2 m / s, and the energy density of the second laser is 0.5~3 J / cm². 2 The pulse width of the second laser is 1~10ps.

[0016] According to some embodiments of this application, another aspect of this application provides a fabrication apparatus for a back-contact solar cell, used to fabricate any of the aforementioned back-contact solar cells. The fabrication apparatus for the back-contact solar cell includes: a first laser processing device for providing a substrate, the substrate having opposing first and second surfaces, the first surface including alternately arranged first and second regions, and forming a first material layer on the first surface; performing a first laser processing on the first material layer located in the second region to obtain a second material layer, the material of the first material layer including doped silicon oxynitride, the silicon oxynitride being an amorphous-nanocrystalline dual-phase structure; a doping device for performing a diffusion treatment on the first material layer that has not undergone the first laser processing to obtain a first functional layer; a second laser processing device for performing a second laser processing on the second material layer to obtain a second functional layer, wherein the energy density of the second laser processing is greater than the energy density of the first laser processing; a first film growth device for forming a first passivation layer and a first electrode on the side of the first functional layer away from the substrate; and a second film growth device for forming a second passivation layer and a second electrode on the side of the second functional layer away from the substrate.

[0017] According to some embodiments of this application, another aspect of this application provides a tandem battery, including: a back-contact solar cell, wherein the back-contact solar cell is any of the back-contact solar cells described above, or a back-contact solar cell prepared by any of the back-contact solar cell preparation methods described above; and a perovskite solar cell electrically connected to the back-contact solar cell.

[0018] According to some embodiments of this application, another aspect of this application provides a photovoltaic module, including: a battery string, formed by connecting multiple back-contact solar cells of any one of the described methods, or back-contact solar cells prepared by any one of the described methods, or the stacked cells; an encapsulation layer for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation layer away from the battery string.

[0019] The technical solution provided in this application has at least the following advantages:

[0020] By setting a first functional layer in a first region and a second functional layer in a second region, the materials of the first and second functional layers include silicon oxynitride containing doped elements. The network framework composed of oxygen and silicon elements can realize the tunneling function, and the doped elements can realize the doping conductivity function. Therefore, the first and second functional layers can replace the tunneling oxide layer and the doped conductive layer in the prior art back contact cell, respectively, and can achieve the same performance. Compared with the prior art process that requires the preparation of two film layers, this solution only requires the preparation of one film layer, which can reduce the process steps and thus reduce the process complexity, solving the technical problem of how to reduce the process complexity of back contact solar cell preparation. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a back contact battery according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the structure of a back contact battery according to another embodiment of this application;

[0024] Figure 3This is a schematic flowchart illustrating a method for preparing a back contact battery according to an embodiment of this application.

[0025] The above figures include the following reference numerals:

[0026] 10. Substrate; 101. First region; 102. Second region; 11. First functional layer; 12. First passivation layer; 13. First electrode; 14. First antireflection layer; 21. Second functional layer; 22. Second passivation layer; 23. Second electrode; 24. Second antireflection layer; 31. Third passivation layer; 32. Third antireflection layer. Detailed Implementation

[0027] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0030] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0031] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0032] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0033] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0034] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0035] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0036] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0037] As is known from the background art, the fabrication process of back-contact solar cells is complex. To solve the above problems, embodiments of this application provide a back-contact solar cell, a method for fabricating a back-contact solar cell, equipment for fabricating a back-contact solar cell, a tandem cell, and a photovoltaic module, such as... Figure 1 and Figure 2 As shown, the back-contact solar cell includes:

[0038] The substrate 10 has opposing first and second surfaces, wherein the first surface includes alternately arranged first region 101 and second region 102.

[0039] The substrate 10 is used to receive incident light and generate photogenerated carriers. The substrate 10 can be doped with either an N-type or a P-type dopant. The N-type dopant can be any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type dopant can be any one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In). The first region 101 and the second region 102 extend in a direction parallel to the first surface. In practical applications, in subsequent fabrication processes, a first electrode 13 is further formed on one side of the first region 101, and a second electrode 23 is further formed on one side of the second region 102. Along the direction parallel to the first surface, the width of the first region 101 can be greater than the width of the first electrode 13; similarly, the width of the second region 102 can also be greater than the width of the second electrode 23.

[0040] The first functional layer 11, the first passivation layer 12, and the first electrode 13 are located in the first region 101. The first passivation layer 12 is located on the side of the first functional layer 11 away from the substrate 10, and the first electrode 13 is located on the side of the first functional layer 11 away from the substrate 10 and is electrically connected to the first functional layer 11.

[0041] The first functional layer 11 combines the functions of a tunneling oxide layer and a doped conductive layer. It allows minority carriers to be blocked while majority carriers tunnel through, achieving selective carrier contact, and also provides a low-resistance current conduction path, constructing a selective carrier collection structure. The first passivation layer 12 can be a single-layer or multi-layer structure. The material of the first passivation layer 12 can be one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide. The first electrode 13 passes through the first passivation layer 12 and contacts the first functional layer 11. The material of the first electrode 13 can include one or more of aluminum, silver, gold, nickel, molybdenum, or copper.

[0042] The second functional layer 21, the second passivation layer 22, and the second electrode 23 are located in the second region 102. The second passivation layer 22 is located on the side of the second functional layer 21 away from the substrate 10, and the second electrode 23 is located on the side of the second functional layer 21 away from the substrate 10 and is electrically connected to the second functional layer 21.

[0043] The aforementioned second functional layer 21 combines the functions of a tunneling oxide layer and a doped conductive layer. It allows minority carriers to be blocked while majority carriers tunnel through, achieving selective carrier contact, and also provides a low-resistance current conduction path, constructing a selective carrier collection structure. The second passivation layer 22 can be a single-layer or multilayer structure, and its material can be one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide. The second electrode 23 penetrates the second passivation layer 22 and contacts the second functional layer 21. The material of the second electrode 23 can include one or more of aluminum, silver, gold, nickel, molybdenum, or copper.

[0044] The first functional layer 11 includes silicon oxynitride containing a first doping element, and the second functional layer 21 includes silicon oxynitride containing a second doping element. The silicon oxynitride is an amorphous-nanocrystalline dual-phase structure, and the first doping element and the second doping element are different.

[0045] The first and second functional layers described above are amorphous and contain embedded nanocrystal clusters. A large number of grain boundaries exist between the nanocrystalline and amorphous phases in the aforementioned amorphous-nanocrystalline dual-phase structure, which is beneficial for carrier transport. The size of the nanocrystalline phase is 1~100 nm. In practical applications, the doping elements described above are not limited and can be any doping element capable of achieving conductivity.

[0046] The back-contact solar cell of this application includes a substrate having opposing first and second surfaces. The first surface includes alternating first and second regions. A first functional layer, a first passivation layer, and a first electrode are located in the first region. A second functional layer, a second passivation layer, and a second electrode are located in the second region. The materials of the first and second functional layers include silicon oxynitride, which has an amorphous-nanocrystalline dual-phase structure. The first and second doping elements are different. By setting the first functional layer in the first region and the second functional layer in the second region, and by using doped silicon oxynitride, the network framework composed of oxygen and silicon elements enables tunneling, and the doping elements enable doping conductivity. Therefore, the first and second functional layers can respectively replace the tunneling oxide layer and the doped conductive layer in existing back-contact solar cells, achieving the same performance. Compared to the existing process requiring two film layers, this solution only requires one film layer, reducing process steps and thus lowering process complexity. This solves the technical problem of reducing the process complexity of back-contact solar cell fabrication.

[0047] In some embodiments, such as Figure 1 and Figure 2 As shown, the thickness of the first functional layer 11 is 150~200nm. The first functional layer 11 is within the above thickness range, which can ensure the function of the first functional layer 11 and prevent the thickness of the first functional layer 11 from affecting the overall thickness of the back contact solar cell.

[0048] In practical applications, the thickness of the first functional layer 11 can be any one of 150nm, 160nm, 170nm, 180nm, 190nm, and 200nm, or between any two values.

[0049] In other embodiments, such as Figure 1 and Figure 2 As shown, the thickness of the second functional layer 21 is 100~150nm. The second functional layer 21 is within this thickness range, which ensures its functionality while preventing excessive thickness from affecting the overall thickness of the back contact solar cell.

[0050] In practical applications, the thickness of the second functional layer 21 can be any value among 100nm, 110nm, 120nm, 130nm, 140nm, and 150nm, or between any two values. In practical applications, the thickness of the second functional layer can be greater than the thickness of the first functional layer.

[0051] To further improve the conductivity of the first and second functional layers, the back-contact solar cell satisfies at least one of the following: the first doping element is a group III element; the second doping element is a group V element. The material configuration of the first and second functional layers, i.e., adding the aforementioned group III or group V element to the material, can further improve the conductivity of the first and second functional layers.

[0052] In practical applications, the first doping element can be a group III element such as boron and gallium, and the second doping element can be a group V element such as phosphorus and arsenic.

[0053] In other embodiments, to further increase the absorption rate of the first and second functional films for lasers of a specific wavelength and promote their densification in response to laser-induced phase transition, the first and second doping elements may further include trace amounts of cerium and zirconium, with a doping concentration of approximately 1.07 × 10⁻⁶. 19 ~4.26×10 19 atoms / cm 3 .

[0054] In some embodiments, such as Figure 1 and Figure 2 As shown, the back-contact solar cell satisfies at least one of the following: in the first functional layer 11, the doping concentration of the first doped element is 5.0 × 10⁻⁶. 19 ~5.0×10 20 atoms / cm 3 In the second functional layer 21, the doping concentration of the second element is 1.0 × 10⁻⁶. 20 ~7.5×10 20 atoms / cm 3 The doping concentrations of the first and second doping elements are within the aforementioned concentration range, which can provide a suitable doping concentration range and further improve the conductivity of the first functional layer 11 and the second functional layer 21.

[0055] In other words, the doping concentration of the first dopant element can be 5.0 × 10⁻⁶. 19 atoms / cm 3 1.0×10 20 atoms / cm 3 2.5×10 20 atoms / cm 3 3.5×10 20 atoms / cm 3 4.5×10 20 atoms / cm 3 and 5.0×10 20atoms / cm 3 The doping concentration of the second dopant element can be any one of the values ​​in the range, or between any two values. 20 atoms / cm 3 2.0×10 20 atoms / cm 3 3.5×10 20 atoms / cm 3 4.5×10 20 atoms / cm 3 5.5×10 20 atoms / cm 3 and 7.5×10 20 atoms / cm 3 The atomic concentration of the first dopant element is any one of the values ​​in the range of 0.1% to 1.0%, or between any two values. In other embodiments, the atomic concentration of the second dopant element is any one of the values ​​in the range of 0.2% to 1.5%, or between any two values. In practical applications, the doping concentrations of the first and second dopant elements can be measured through elemental composition analysis and electrical performance characterization. Elemental composition analysis directly measures the number of atoms of the dopant element in the material, and then calculates the doping concentration based on the number of atoms. For example, this can be achieved using secondary ion mass spectrometry (SIMS) and inductively coupled plasma mass spectrometry (ICP-MS). Electrical performance characterization indirectly calculates the electroactive doping concentration by measuring changes in electrical properties (such as resistivity and capacitance) caused by doping. For example, this can be achieved using the four-probe method, capacitance-voltage method, and thermodynamic method. As an example, the concentration of the first dopant element in the first functional layer can be determined as follows: First, select a certain range of the first functional layer, place four probes at equal intervals on the surface of the first functional layer, pass a constant current through the two outer probes, and measure the voltage between the two inner probes. Based on the measured voltage and current, the thin-film resistance or resistivity of the material can be calculated, and then the average doping concentration can be deduced (the higher the doping concentration, the lower the resistivity).

[0056] In other embodiments, such as Figure 2As shown, the aforementioned back-contact solar cell further includes: a first antireflection layer 14 located in the first region 101, situated on the side of the first passivation layer 12 away from the first functional layer 11; a second antireflection layer 24 located in the second region 102, situated on the side of the second passivation layer 22 away from the second functional layer 21; a third passivation layer 31 located on the second surface; and a third antireflection layer 32 located on the side of the third passivation layer 31 away from the substrate 10. By employing the first antireflection layer 14, the second antireflection layer 24, the third antireflection layer 32, and the third passivation layer 31, the surface recombination current density of the back-contact solar cell can be further reduced, thereby further improving the photoelectric conversion efficiency of the back-contact solar cell.

[0057] The materials of the first antireflective layer 14, the second antireflective layer 24, and the third antireflective layer 32 can be at least one of aluminum oxide and silicon oxynitride. The third passivation layer 31 can be a single-layer structure or a stacked structure, and the material of the third passivation layer 31 can be one or more of the following materials: silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0058] In some other embodiments, such as Figure 1 and Figure 2 As shown, the minimum distance between the first functional layer 11 and the second surface is the first distance, and the minimum distance between the second functional layer 21 and the second surface is the second distance. The first distance and the second distance are different. This arrangement can achieve electrical isolation between the first electrode 13 and the second electrode 23, thereby further improving the reliability of the back contact battery.

[0059] The first distance mentioned above is the perpendicular distance between the first functional layer 11 and the second surface along the thickness direction of the back-contact solar cell. The second distance mentioned above is the perpendicular distance between the second functional layer 21 and the second surface along the thickness direction of the back-contact solar cell. In practical applications, the first distance can be greater than the second distance.

[0060] In another typical embodiment of this application, a method for fabricating a back-contact solar cell is provided, for fabricating any of the aforementioned back-contact solar cells, such as... Figure 3 As shown, the fabrication method of the above-mentioned back-contact solar cell includes:

[0061] Step S501: Provide a substrate having a first surface and a second surface, the first surface including alternating first and second regions, and form a first material layer on the first surface. Perform a first laser treatment on the first material layer located in the second region to obtain a second material layer. The material of the first material layer includes silicon oxynitride containing doped elements, and the silicon oxynitride is an amorphous-nanocrystalline dual-phase structure.

[0062] In practical applications, the resistivity of the above-mentioned substrate can be 1~3Ω. The thickness can be 100μm~150μm. Before forming the first material layer on the first surface, the substrate can be polished on both sides to remove the saw-damaged layer and obtain a smooth surface, which is beneficial for the subsequent deposition of a high-quality film layer. The first material layer can be formed by plasma-enhanced chemical vapor deposition (PECVD). In addition, the first material layer located in the second region can be subjected to a first laser treatment using a preset pattern. The first region and the second region extend in a direction parallel to the first surface. Since the first material layer is an amorphous-nanocrystalline dual-phase structure, the first material layer undergoes a phase transition from a "porous and loose state" to a "dense state". Its densified portion has a strong barrier to the diffusion of dopant sources and can be used as a dopant barrier layer for subsequent diffusion processing.

[0063] Step S502: Diffusion treatment is performed on the first material layer that has not undergone the first laser treatment to obtain the first functional layer;

[0064] In fact, since the first material layer that has undergone laser treatment has already formed a second material layer with doping barrier capability, the aforementioned diffusion treatment of the first material layer will not have a significant impact on the second material layer, so that the first material layer that has not undergone the aforementioned first laser treatment can form the aforementioned first functional layer.

[0065] Step S503: Perform a second laser treatment on the second material layer to obtain a second functional layer, wherein the energy density of the second laser treatment is greater than the energy density of the first laser treatment.

[0066] The energy density of the second laser treatment is greater than that of the first laser treatment; that is, the first laser treatment is a low-energy-density laser treatment, while the second laser treatment is a high-energy-density laser treatment. After the second material layer undergoes high-energy-density laser treatment (i.e., the second laser treatment), the film layer in the irradiated area will instantly undergo thermal decomposition and vaporization, exposing the underlying substrate. Simultaneously, the released dopants will dope the exposed substrate in situ, forming the second functional layer. It should be noted that the energy densities mentioned above are all single-pulse laser energy densities. In practical applications, during the laser treatment of the second material layer, a portion of the isolation area can be left untreated by the second laser treatment to isolate the first and second regions.

[0067] Step S504: A first passivation layer and a first electrode are formed on the side of the first functional layer away from the substrate;

[0068] The first passivation layer can be formed using chemical vapor deposition methods such as low-pressure chemical vapor deposition (LPCVD) and PECVD. The first electrode can be formed using screen printing, electroplating, vapor deposition, and inkjet printing. Before forming the first passivation layer and the first electrode, the structure obtained in the above steps can be wet-cleaned to remove laser damage and residues that may have been generated by the first and second laser treatments. After forming the first passivation layer, the process further includes: forming a first antireflection layer on the side of the first passivation layer in the first region away from the first functional layer; forming a third passivation layer on the second surface; and forming a third antireflection layer on the side of the third passivation layer away from the substrate.

[0069] Step S505: A second passivation layer and a second electrode are formed on the side of the second functional layer away from the substrate.

[0070] The second passivation layer can be formed using chemical vapor deposition methods such as LPCVD and PECVD. The second electrode can be formed using screen printing, electroplating, vapor deposition, and inkjet printing. After forming the second passivation layer, a second antireflection layer is formed on the side of the second passivation layer in the second region away from the second functional layer. In the above preparation method, since damage to the silicon wafer caused by multiple high-temperature and wet chemical processes is avoided, and in-situ doping and an amorphous-nanocrystalline dual-phase structure of the first material layer are used, an open-circuit voltage greater than 0.740V and a photoelectric conversion efficiency greater than 26% can be obtained in the preparation of N-TBC cells, while the production cost is significantly reduced.

[0071] The method for fabricating a back contact battery according to this application firstly involves providing a substrate having opposing first and second surfaces. The first surface includes alternating first and second regions, and a first material layer is formed on the first surface. The first material layer located in the second region is subjected to a first laser treatment to obtain a second material layer. The first material layer without the first laser treatment is then subjected to a diffusion treatment to obtain a first functional layer. Next, the second material layer is subjected to a second laser treatment to obtain a second functional layer, wherein the energy density of the second laser treatment is greater than that of the first laser treatment. Finally, a first passivation layer and a first electrode are formed on the side of the first functional layer away from the substrate; a second passivation layer and a second electrode are formed on the side of the second functional layer away from the substrate. During the first and second laser treatments, due to the amorphous-nanocrystalline dual-phase structure of the first material layer, after the first material layer located in the second region undergoes a low-energy-density laser treatment (i.e., the first laser treatment), the first material layer undergoes a phase transition from a "porous and loose state" to a "dense state." The densified portion has a strong blocking ability against the diffusion of dopant sources and can serve as a doping barrier layer for subsequent diffusion treatment. After the second material layer is subjected to high-energy-density laser treatment (i.e., second laser treatment), the film layer in the irradiated area undergoes instantaneous thermal decomposition and vaporization, exposing the underlying substrate. Simultaneously, the released dopants dope the exposed substrate in situ, forming the second functional layer. This process replaces the complex patterning and acid etching cleaning steps in the existing back-contact solar cell fabrication process, reducing the number of process steps and thus lowering the process complexity. This solves the technical problem of how to reduce the process complexity of back-contact solar cell fabrication.

[0072] Step S501 can be implemented as follows: Step S5011, a first gas is introduced into the cavity containing the substrate, and a predetermined power is applied. The first gas includes a nitrogen source gas, an oxygen source gas, a silicon source gas, a dopant source gas, and an inert gas. The dopant source gas includes a metalloid element or a metallic element. The temperature of the cavity is 380~420℃, the pressure of the cavity is 80~110Pa, and the predetermined power is 20~35W. Using the first gas and applying the predetermined power can further improve the reliability of forming the first material layer.

[0073] The temperature of the aforementioned cavity can be any one of 380°C, 390°C, 400°C, 410°C, and 420°C, or between any two of these values. The pressure of the aforementioned cavity can be any one of 80Pa, 90Pa, 100Pa, and 110Pa, or between any two of these values. The aforementioned predetermined power can be any one of 20W, 25W, 30W, and 35W, or between any two of these values. In some embodiments, the aforementioned first gas may include silane (as a silicon source gas), ammonia (as a nitrogen source gas), nitrous oxide (as an oxygen source gas), borane (as a dopant source gas), and helium (as an inert gas).

[0074] In some embodiments, the gas flow rate ratio of the nitrogen source gas, oxygen source gas, silicon source gas, and dopant source gas is (3~8):(1~4):(8~15):(0.5~0.3). The gas flow rate ratio being within the aforementioned range can further improve the reliability of forming the first material layer.

[0075] In other words, in the aforementioned first gas, the gas flow rates of nitrogen source gas, oxygen source gas, silicon source gas, and dopant source gas gradually decrease. The gas flow rate of the aforementioned inert gas can be the same as that of the aforementioned dopant source gas to dilute the inert gas. The aforementioned silicon source gas can be used to form the main framework of the first material layer. The silicon source gas flow rate being within the aforementioned proportional range can control the deposition rate and form a continuous film layer, while preventing silicon enrichment and affecting the reaction of the nitrogen and oxygen source gases. The nitrogen source gas can form Si-N bonds with the silicon source gas. The flow rate ratio of the nitrogen source gas to the silicon source gas affects the refractive index, stress, stoichiometry, and passivation quality of the first material layer. The nitrogen source gas flow rate being within the aforementioned proportional range ensures sufficient nitrogen content to achieve good passivation and dielectric properties. The aforementioned oxygen source gas can provide oxygen to form Si-O bonds, thereby adjusting the laser absorption rate and thermodynamic properties of the first material layer and preventing densification or ablation phase transitions under different laser parameters. The aforementioned oxygen source gas can also synergistically work with the nitrogen source gas to regulate the densification capability of the first material layer.

[0076] In some possible implementations, the nitrogen source gas can be NH3, the oxygen source gas N2O, the silicon source gas can be SiH4, and the dopant source gas can be B2H6.

[0077] The above step S501 can also be implemented in other ways, for example: using a first laser to scan the first material layer to obtain the second material layer, wherein the light source of the first laser is infrared light, the scanning speed of the first laser is 1m / s to 10m / s, and the energy density of the first laser is 0 to 0.5J / cm². 2The pulse width of the first laser is 10~100ns. This method can further improve the reliability of forming the second material layer.

[0078] In practical applications, the wavelength of the first laser can be 1064 nm. Using this wavelength results in a better and more uniform thermal effect, making it suitable for the aforementioned densification process. The scanning speed of the first laser can be any value from 1 m / s, 2 m / s, 3 m / s, 4 m / s, 5 m / s, 6 m / s, 7 m / s, 8 m / s, 9 m / s, and 10 m / s, or any value between any two of these values. The energy density of the first laser can be 0.1 J / cm³. 2 0.2J / cm 2 0.3J / cm 2 0.4J / cm 2 0.5J / cm 2 The pulse width of the first laser can be any one of the values ​​in the above range, or it can be any two of the above values.

[0079] Step S502 above can be achieved through the following steps: Step S5021, introducing a second gas into the cavity containing the substrate for a predetermined duration, wherein the temperature of the cavity is 800~900℃, and the predetermined duration is 10~20 minutes. This method can further improve the reliability of forming the first functional layer.

[0080] The second gas mentioned above can be phosphorus oxychloride. The temperature of the cavity mentioned above can be any one of 800℃, 850℃, and 900℃, or any value between any two of the above values. The predetermined duration mentioned above can be any one of 10min, 15min, and 20min, or any value between any two of the above values.

[0081] The above step S503 can be achieved through the following steps: Step S5031, using a second laser to scan the second material layer to obtain the second functional layer, wherein the light source of the second laser is green light or ultraviolet light, the scanning speed of the second laser is 0.5~2m / s, and the energy density of the second laser is 0.5~3J / cm². 2 The pulse width of the second laser is 1~10 ps. This method can further improve the reliability of forming the second functional layer.

[0082] The wavelength of the second laser can be either 532nm or 355nm. The 532nm wavelength second laser offers higher precision and is more suitable for ablation processes; the 355nm wavelength second laser, with its shorter wavelength, exhibits better material absorption, enabling cold processing and resulting in a smaller heat-affected zone, making it suitable for fine patterning. The scanning speed of the second laser can be any value from 0.5m / s, 1m / s, 1.5m / s, and 2m / s, or any value between two of these. The energy density of the second laser is 0.5J / cm³. 2 1J / cm 2 1.5J / cm 2 2J / cm 2 2.5J / cm 2 3J / cm 2 Any one of the values ​​in the above, or any two of the above values. The pulse width of the second laser is any one of 1ps, 5ps, and 10ps, or any two of the above values.

[0083] In another typical embodiment of this application, a fabrication apparatus for a back-contact solar cell is provided, used to fabricate any of the aforementioned back-contact solar cells. The fabrication apparatus for the back-contact solar cell includes:

[0084] A first laser processing apparatus is used to provide a substrate having opposing first and second surfaces, the first surface including alternating first and second regions, and forming a first material layer on the first surface, performing a first laser processing on the first material layer located in the second region to obtain a second material layer, wherein the material of the first material layer includes silicon oxynitride containing doped elements, and the silicon oxynitride is an amorphous-nanocrystalline dual-phase structure.

[0085] In practical applications, the resistivity of the above-mentioned substrate can be 1~3Ω. The thickness can be 100μm~150μm. Before forming the first material layer on the first surface, the substrate can be polished on both sides to remove the saw-damaged layer and obtain a smooth surface, which is beneficial for the subsequent deposition of a high-quality film layer. The first material layer can be formed by plasma-enhanced chemical vapor deposition (PECVD). In addition, the first material layer located in the second region can be subjected to a first laser treatment using a preset pattern. The first region and the second region extend in a direction parallel to the first surface. Since the first material layer is an amorphous-nanocrystalline dual-phase structure, the first material layer undergoes a phase transition from a "porous and loose state" to a "dense state". Its densified portion has a strong barrier to the diffusion of dopant sources and can be used as a dopant barrier layer for subsequent diffusion processing.

[0086] A doping device is used to perform diffusion treatment on the first material layer that has not undergone the first laser treatment to obtain a first functional layer;

[0087] In fact, since the first material layer that has undergone the first laser treatment has already formed a second material layer with doping barrier capability, the aforementioned diffusion treatment of the first material layer will not have a significant impact on the second material layer, so that the first material layer that has not undergone the first laser treatment can form the first functional layer.

[0088] A second laser processing device is used to perform a second laser processing on the second material layer to obtain a second functional layer, wherein the energy density of the second laser processing is greater than the energy density of the first laser processing.

[0089] The energy density of the second laser treatment is greater than that of the first laser treatment; that is, the first laser treatment is a low-energy-density laser treatment, while the second laser treatment is a high-energy-density laser treatment. After the second material layer undergoes high-energy-density laser treatment (i.e., the second laser treatment), the film layer in the irradiated area will instantly undergo thermal decomposition and vaporization, exposing the underlying substrate. Simultaneously, the released dopants will dope the exposed substrate in situ, forming the second functional layer. It should be noted that the energy densities mentioned above are all single-pulse laser energy densities. In practical applications, during the laser treatment of the second material layer, a portion of the isolation area can be left untreated by the second laser treatment to isolate the first and second regions.

[0090] A first film growth apparatus is used to form a first passivation layer and a first electrode on the side of the first functional layer away from the substrate.

[0091] The first passivation layer can be formed using chemical vapor deposition methods such as low-pressure chemical vapor deposition (LPCVD) and PECVD. The first electrode can be formed using screen printing, electroplating, vapor deposition, and inkjet printing. Before forming the first passivation layer and the first electrode, the structure obtained in the above steps can be wet-cleaned to remove laser damage and residues that may have been generated by the first and second laser treatments. After forming the first passivation layer, the process further includes: forming a first antireflection layer on the side of the first passivation layer in the first region away from the first functional layer; forming a third passivation layer on the second surface; and forming a third antireflection layer on the side of the third passivation layer away from the substrate.

[0092] The second film growth apparatus is used to form a second passivation layer and a second electrode on the side of the second functional layer away from the substrate.

[0093] The second passivation layer can be formed using chemical vapor deposition methods such as low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD). The second electrode can be formed using screen printing, electroplating, vapor deposition, and inkjet printing. After forming the second passivation layer, a second antireflection layer is formed on the side of the second passivation layer in the second region away from the second functional layer. In the above preparation method, by avoiding damage to the silicon wafer from multiple high-temperature and wet chemical processes, and by employing in-situ doping and an amorphous-nanocrystalline dual-phase structure as the first material layer, an open-circuit voltage greater than 0.740V and a photoelectric conversion efficiency greater than 26% can be obtained in the fabrication of N-TBC cells, while significantly reducing production costs.

[0094] The fabrication apparatus for the back contact battery of this application includes a first laser processing device for providing a substrate having opposing first and second surfaces. The first surface includes alternating first and second regions, and a first material layer is formed on the first surface. The first material layer located in the second region is subjected to a first laser processing to obtain a second material layer. A doping device is used to perform a diffusion processing on the first material layer that has not undergone the first laser processing to obtain a first functional layer. A second laser processing device is used to perform a second laser processing on the second material layer to obtain a second functional layer, wherein the energy density of the second laser processing is greater than the energy density of the first laser processing. A first film layer growth device is used to form a first passivation layer and a first electrode on the side of the first functional layer away from the substrate. A second film layer growth device is used to form a second passivation layer and a second electrode on the side of the second functional layer away from the substrate. During the first and second laser treatments, due to the material properties of the amorphous-nanocrystalline dual-phase structure of the first material layer, after low-energy-density laser treatment (i.e., the first laser treatment) on the first material layer located in the second region, the first material layer undergoes a phase transition from a "porous and loose state" to a "dense state." Its densified portion has a strong ability to block the diffusion of dopant sources and can serve as a dopant barrier layer for subsequent diffusion treatment. After high-energy-density laser treatment (i.e., the second laser treatment) on the second material layer, the film layer in the irradiated area undergoes instantaneous thermal decomposition and vaporization, exposing the underlying substrate. Simultaneously, the released dopants dope the exposed substrate in situ, forming the second functional layer. These steps replace the complex patterning and acid etching cleaning steps in the existing back-contact solar cell fabrication process, reducing process steps and thus lowering process complexity, solving the technical problem of how to reduce the process complexity of back-contact solar cell fabrication.

[0095] In another typical embodiment of this application, a stacked battery is provided, comprising:

[0096] The back-contact solar cell is any of the back-contact solar cells described above, or a back-contact solar cell prepared by any of the back-contact solar cell preparation methods described above.

[0097] The perovskite solar cell is electrically connected to the aforementioned back-contact solar cell.

[0098] The perovskite solar cell described above serves as the top cell in a tandem solar cell system. In practical applications, a buffer layer is also included between the back-contact solar cell and the perovskite solar cell. The perovskite solar cell is in close contact with the buffer layer, which in turn is in contact with the back-contact solar cell. This layered structure ensures that photogenerated carriers generated from the perovskite solar cell can be effectively transferred to the back-contact solar cell through the buffer layer, achieving efficient charge separation and collection, reducing carrier recombination losses, and thus improving the output current and open-circuit voltage of the tandem solar cell.

[0099] In another typical embodiment of this application, a photovoltaic module is provided, comprising:

[0100] A battery string is formed by connecting multiple back-contact solar cells of any one of the above-mentioned types, or back-contact solar cells prepared by any of the above-mentioned methods of preparing back-contact solar cells, or the above-mentioned tandem cells.

[0101] Two adjacent battery strings can be electrically connected via conductive strips. In some embodiments, the electrodes of the same polarity in the stacked batteries face the same direction, and the conductive strips connect the electrodes of different polarities in two adjacent stacked batteries. In other embodiments, the stacked batteries can also be arranged according to electrodes of different polarities, i.e., the electrodes of adjacent battery cells are arranged in the order of first polarity, second polarity, and first polarity, respectively, and the conductive strips connect two adjacent battery cells on the same side. In some embodiments, there is no gap between the battery cells, i.e., the battery cells overlap each other.

[0102] An encapsulation layer is used to cover the surface of the aforementioned battery string;

[0103] Specifically, the encapsulation layer includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers either the front or back side of the stacked battery string, and the second encapsulation layer covers the other side of the front or back side of the battery string. Specifically, the encapsulation layer material can be at least one of the following organic encapsulation layers: polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film. In practical applications, there is a gap between the first and second encapsulation layers during lamination, but after lamination, the first and second encapsulation layers together form the aforementioned encapsulation layer.

[0104] A cover plate is used to cover the surface of the encapsulation layer that is away from the battery string.

[0105] Specifically, the cover plate can be made of light-transmitting materials such as glass or plastic. Furthermore, the surface of the cover plate facing the encapsulation layer can be uneven, thereby increasing the utilization rate of incident light. The cover plate includes a first cover plate and a second cover plate, the first cover plate being disposed opposite to a first encapsulation layer, and the second cover plate being disposed opposite to a second encapsulation layer.

[0106] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0107] 1. The back contact solar cell of this application includes a substrate having opposing first and second surfaces. The first surface includes alternating first and second regions. A first functional layer, a first passivation layer, and a first electrode are located in the first region. A second functional layer, a second passivation layer, and a second electrode are located in the second region. The materials of the first and second functional layers include silicon oxynitride, which has an amorphous-nanocrystalline dual-phase structure. The first dopant element and the second dopant element are different. By setting the first functional layer in the first region and the second functional layer in the second region, and by using silicon oxynitride containing doped elements as the material of the first and second functional layers, the network framework composed of oxygen and silicon elements can achieve tunneling functionality, and the doped elements can achieve doping conductivity. Therefore, the first and second functional layers can respectively replace the tunneling oxide layer and the doped conductive layer in the prior art back contact solar cell, and can achieve the same performance. Compared with the prior art process that requires the preparation of two film layers, this solution only requires the preparation of one film layer, which can reduce the process steps and thus reduce the process complexity, solving the technical problem of how to reduce the process complexity of back contact solar cell fabrication.

[0108] 2. The method for fabricating the back contact battery of this application includes: First, providing a substrate having opposing first and second surfaces. The first surface includes alternating first and second regions, and forming a first material layer on the first surface. The first material layer located in the second region is subjected to a first laser treatment to obtain a second material layer. Then, the first material layer without the first laser treatment is subjected to a diffusion treatment to obtain a first functional layer. Next, the second material layer is subjected to a second laser treatment to obtain a second functional layer, wherein the energy density of the second laser treatment is greater than the energy density of the first laser treatment. Finally, a first passivation layer and a first electrode are formed on the side of the first functional layer away from the substrate; a second passivation layer and a second electrode are formed on the side of the second functional layer away from the substrate. During the first and second laser treatments, due to the amorphous-nanocrystalline dual-phase structure of the first material layer, after the first material layer located in the second region undergoes a low-energy-density laser treatment (i.e., the first laser treatment), the first material layer undergoes a phase transition from a "porous and loose state" to a "dense state." The densified portion has a strong blocking ability against the diffusion of dopant sources and can serve as a doping barrier layer for subsequent diffusion treatment. After the second material layer is subjected to high-energy-density laser treatment (i.e., second laser treatment), the film layer in the irradiated area undergoes instantaneous thermal decomposition and vaporization, exposing the underlying substrate. Simultaneously, the released dopants dope the exposed substrate in situ, forming the second functional layer. This process replaces the complex patterning and acid etching cleaning steps in the existing back-contact solar cell fabrication process, reducing the number of process steps and thus lowering the process complexity. This solves the technical problem of how to reduce the process complexity of back-contact solar cell fabrication.

[0109] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A back-contact solar cell, characterized in that, include: A substrate having opposing first and second surfaces, the first surface comprising alternating first and second regions; The first functional layer, the first passivation layer, and the first electrode are located in the first region. The first passivation layer is located on the side of the first functional layer away from the substrate, and the first electrode is located on the side of the first functional layer away from the substrate and is electrically connected to the first functional layer. The second functional layer, the second passivation layer, and the second electrode are located in the second region. The second passivation layer is located on the side of the second functional layer away from the substrate, and the second electrode is located on the side of the second functional layer away from the substrate and is electrically connected to the second functional layer. The first functional layer includes silicon oxynitride containing a first doping element, and the second functional layer includes silicon oxynitride containing a second doping element. The silicon oxynitride has an amorphous-nanocrystalline dual-phase structure, and the first doping element and the second doping element are different.

2. The back-contact solar cell according to claim 1, characterized in that, The thickness of the first functional layer is 150~200nm.

3. The back-contact solar cell according to claim 1, characterized in that, The thickness of the second functional layer is 100~150nm.

4. The back-contact solar cell according to claim 1, characterized in that, The back-contact solar cell satisfies at least one of the following: The first doping element is a group III element; The second doping element is a group V element.

5. The back-contact solar cell according to claim 1, characterized in that, The back-contact solar cell satisfies at least one of the following: In the first functional layer, the doping concentration of the first dopant element is 5.0 × 10⁻⁶. 19 ~5.0×10 20 atoms / cm 3 ; In the second functional layer, the doping concentration of the second doped element is 1.0 × 10⁻⁶. 20 ~7.5×10 20 atoms / cm 3 .

6. The back-contact solar cell according to any one of claims 1 to 5, characterized in that, The distance between the first functional layer and the second surface is a first distance, and the distance between the second functional layer and the second surface is a second distance, wherein the first distance is greater than the second distance.

7. A method for fabricating a back-contact solar cell, characterized in that, The method for preparing the back-contact solar cell according to any one of claims 1 to 6 includes: A substrate is provided, the substrate having opposing first and second surfaces, the first surface including alternating first and second regions, and a first material layer is formed on the first surface. The first material layer located in the second region is subjected to a first laser treatment to obtain a second material layer. The material of the first material layer includes silicon oxynitride containing doped elements, and the silicon oxynitride is an amorphous-nanocrystalline dual-phase structure. A diffusion process is performed on the first material layer that has not undergone the first laser treatment to obtain a first functional layer; The second material layer is subjected to a second laser treatment to obtain a second functional layer, wherein the energy density of the second laser treatment is greater than the energy density of the first laser treatment; A first passivation layer and a first electrode are formed on the side of the first functional layer away from the substrate; A second passivation layer and a second electrode are formed on the side of the second functional layer away from the substrate.

8. The method for preparing a back-contact solar cell according to claim 7, characterized in that, A first material layer is formed on the first surface, including: A first gas is introduced into the cavity containing the substrate, and a predetermined power is applied. The first gas includes a nitrogen source gas, an oxygen source gas, a silicon source gas, a doped source gas, and an inert gas. The temperature of the cavity is 380~420℃, the pressure of the cavity is 80~110Pa, and the predetermined power is 20~35W.

9. The method for preparing a back-contact solar cell according to claim 7, characterized in that, The first material layer located in the second region is subjected to a first laser treatment to obtain a second material layer, comprising: The first material layer is scanned using a first laser to obtain the second material layer. The light source of the first laser is infrared light, the scanning speed of the first laser is 1 m / s to 10 m / s, and the energy density of the first laser is 0 to 0.5 J / cm². 2 The pulse width of the first laser is 10~100ns.

10. The method for preparing a back-contact solar cell according to claim 7, characterized in that, A diffusion process is performed on the first material layer that has not undergone the first laser treatment to obtain a first functional layer, comprising: A second gas is introduced into the cavity containing the substrate and continued for a predetermined time, wherein the temperature of the cavity is 800~900℃ and the predetermined time is 10~20min.

11. The method for preparing a back-contact solar cell according to any one of claims 7 to 10, characterized in that, The second material layer is subjected to a second laser treatment to obtain a second functional layer, comprising: The second material layer is obtained by scanning it with a second laser. The light source of the second laser is green light or ultraviolet light. The scanning speed of the second laser is 0.5~2 m / s, and the energy density of the second laser is 0.5~3 J / cm². 2 The pulse width of the second laser is 1~10ps.

12. An apparatus for fabricating a back-contact solar cell, characterized in that, The apparatus for fabricating the back-contact solar cell according to any one of claims 1 to 6 comprises: A first laser processing apparatus is used to provide a substrate having opposing first and second surfaces, the first surface including alternating first and second regions, and forming a first material layer on the first surface, performing a first laser processing on the first material layer located in the second region to obtain a second material layer, wherein the material of the first material layer includes silicon oxynitride containing doped elements, and the silicon oxynitride is an amorphous-nanocrystalline dual-phase structure; A doping device is used to perform diffusion treatment on the first material layer that has not undergone the first laser treatment to obtain a first functional layer; A second laser processing device is used to perform a second laser processing on the second material layer to obtain a second functional layer, wherein the energy density of the second laser processing is greater than the energy density of the first laser processing.

13. A stacked battery, characterized in that, include: A back-contact solar cell, wherein the back-contact solar cell is the back-contact solar cell according to any one of claims 1 to 6, or the back-contact solar cell prepared by the preparation method of the back-contact solar cell according to any one of claims 7 to 11; The perovskite cell is electrically connected to the back-contact solar cell.

14. A photovoltaic module, characterized in that, include: A battery string is formed by connecting multiple back-contact solar cells as described in any one of claims 1 to 6, or back-contact solar cells prepared by the method described in any one of claims 7 to 11, or stacked cells as described in claim 13. An encapsulation layer is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulation layer that faces away from the battery string.

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