Solar cell and photovoltaic module

Abstract

The utility model is suitable for the technical field of solar power generation, and provides a solar cell and a photovoltaic assembly, the solar cell comprises a first antireflection film, a first passivation film, a first conductive type area, a semiconductor substrate, a second conductive type area and a second passivation film which are arranged in sequence from a light-facing side to a backlight side, the first antireflection film comprises at least one silicon nitride layer, at least one silicon oxynitride layer and a silicon oxide layer, and the silicon nitride layer, the silicon oxynitride layer and the silicon oxide layer are sequentially distributed in the direction from the position close to the semiconductor substrate to the position away from the semiconductor substrate, through the arrangement, the passivation effect is good, light reflection can be effectively reduced, light absorption can be effectively improved, and the service life of the device is prolonged. The power generation efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar power generation, and particularly relates to a solar cell and a photovoltaic module. Background Art

[0002] A solar cell, also called a solar panel, is one of the core parts of a photovoltaic power generation system, mainly composed of photovoltaic cells, interconnecting bars, bus bars, photovoltaic glass, encapsulant, backsheet, aluminum frame, and junction box, etc. Among them, the photovoltaic cell is the core component for power generation, the interconnecting bar is used to connect the cells, the bus bar is used to collect current, the photovoltaic glass plays a role in protecting the cells, the encapsulant is used for insulation, moisture-proof, anti-ultraviolet and corrosion resistance, the backsheet is located on the back of the module and plays a role in protecting and supporting the cells, the aluminum frame is used to protect the module and facilitate installation, and the junction box is used to connect the external circuit.

[0003] To improve the photoelectric conversion efficiency, a solar cell is also provided with an antireflection film, which is used to reduce the reflection of sunlight, improve the light absorption rate of the solar cell, and thus improve the power generation efficiency of the solar cell. However, the antireflection effect of the antireflection film of the existing solar cell is not good, and the passivation effect is poor, which limits the power generation efficiency of the solar cell. Summary of the Utility Model

[0004] An embodiment of the utility model provides a solar cell and a photovoltaic module, aiming to solve the problem that the antireflection effect of the antireflection film of the existing solar cell is not good, the passivation effect is poor, and the power generation efficiency of the solar cell is limited.

[0005] An embodiment of the utility model is implemented as follows. A solar cell includes a first antireflection film, a first passivation film, a first conductivity type region, a semiconductor substrate, a second conductivity type region, and a second passivation film, which are sequentially arranged from the light-facing side to the backlight side;

[0006] The first antireflection film includes at least one silicon nitride layer, at least one silicon oxynitride layer, and one silicon oxide layer, which are sequentially distributed in the direction from close to the semiconductor substrate to far from the semiconductor substrate.

[0007] Further, two silicon oxynitride layers are provided between the silicon oxide layer and the silicon nitride layer.

[0008] Further, three silicon nitride layers are provided on the side of the silicon oxynitride layer far from the silicon oxide layer.

[0009] Further, the refractive indices of the silicon nitride layer, the silicon oxynitride layer, and the silicon oxide layer decrease in sequence.

[0010] Further, in the direction from close to the semiconductor substrate to far from the semiconductor substrate, the refractive indices of the two silicon oxynitride layers decrease in sequence.

[0011] Further, in the direction from close to the semiconductor substrate to away from the semiconductor substrate, the refractive indices of the three silicon nitride layers gradually decrease.

[0012] Further, the first antireflection film is also disposed on a side surface of the second passivation film away from the second conductivity type region.

[0013] Further, the solar cell further includes a first tunneling layer disposed between the first conductivity type region and the semiconductor substrate.

[0014] Further, the solar cell further includes a second tunneling layer disposed between the second conductivity type region and the semiconductor substrate.

[0015] Further, the solar cell further includes a third doping layer disposed between the semiconductor substrate and the first tunneling layer.

[0016] Further, the solar cell further includes a fourth doping layer disposed between the semiconductor substrate and the second tunneling layer.

[0017] Further, the solar cell further includes a first electrode and a second electrode, the first electrode is connected to the first conductivity type region, and the second electrode is connected to the second conductivity type region.

[0018] Further, the first passivation film and / or the second passivation film is alumina.

[0019] Further, the first tunneling layer and the second tunneling layer include at least one of silicon oxide, silicon nitride, silicon oxynitride, intrinsic amorphous silicon, and intrinsic polycrystalline silicon.

[0020] In a second aspect, the present application further provides a photovoltaic module including the solar cell as described above.

[0021] The beneficial effects of the present application are as follows. The solar cell of the present application includes a first antireflection film, a first passivation film, a first conductivity type region, a semiconductor substrate, a second conductivity type region, and a second passivation film sequentially arranged from the light-facing side to the backlight side. Among them, the first antireflection film includes at least one silicon nitride layer, at least one silicon oxynitride layer, and one silicon oxide layer. The silicon nitride layer, the silicon oxynitride layer, and the silicon oxide layer are sequentially distributed in the direction from close to the semiconductor substrate to away from the semiconductor substrate. Through the above arrangement, the passivation effect is good, the light reflection can be effectively reduced, the light absorption can be increased, and the power generation efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of an embodiment of the solar cell provided by the present application;

[0023] Figure 2It is a schematic structural diagram of a tunneling layer provided in an embodiment of the solar cell of the present application;

[0024] Figure 3 It is a schematic structural diagram of a doped layer provided in an embodiment of the solar cell of the present application;

[0025] Figure 4 It is a schematic diagram of the film layer structure of an antireflection film in an embodiment of the solar cell provided by the present application;

[0026] Figure 5 It is a schematic diagram of the film layer performance data of an antireflection film in an embodiment of the solar cell provided by the present application. Detailed implementation manners

[0027] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present utility model and should not be construed as limiting the present utility model. In addition, it should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0028] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present utility model.

[0029] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "a plurality" means two or more unless otherwise specifically defined.

[0030] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a connection that allows mutual communication; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0031] In the present utility model, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the horizontal height of the first feature is lower than that of the second feature.

[0032] The following disclosure provides many different embodiments or examples for implementing different structures of the present utility model. To simplify the disclosure of the present utility model, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present utility model. In addition, the present utility model may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present utility model provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0033] The solar cell of the present application includes a first antireflection film, a first passivation film, a first conductive type region, a semiconductor substrate, a second conductive type region, and a second passivation film, which are sequentially arranged from the light-facing side to the backlight side. Among them, the first antireflection film includes at least one layer of silicon nitride layer, at least one layer of silicon oxynitride layer, and one layer of silicon oxide layer. The silicon nitride layer, the silicon oxynitride layer, and the silicon oxide layer are sequentially distributed in the direction from being close to the semiconductor substrate to being away from the semiconductor substrate. Through the above settings, the passivation effect is good, which can effectively reduce light reflection, increase light absorption, and improve the power generation efficiency.

[0034] Embodiment 1

[0035] As Figures 1 to 4As shown in the figure, an embodiment of the present application provides a solar cell, including a first antireflection film 100, a first passivation film 200, a first conductivity type region 300, a semiconductor substrate 400, a second conductivity type region 500, and a second passivation film 600, which are arranged in sequence from the light-facing side to the backlight side;

[0036] The first antireflection film 100 includes at least one silicon nitride layer, at least one silicon oxynitride layer, and one silicon oxide layer, which are distributed in sequence along the direction from close to the semiconductor substrate 400 to away from the semiconductor substrate 400.

[0037] In implementation, the solar cell provided by the present application is a cell that requires an antireflection film to be provided on the front side, such as a PERC (Passivated Emitter and Rear Cell) cell, a TOPCon (Tunnel Oxide Passivating Contact) cell, a BC (Back Contact) cell, or other types of solar cells, without limitation.

[0038] Generally, the front side of the solar cell can be regarded as the light-facing side of the cell, and the back side of the solar cell can be regarded as the backlight side of the cell, which will not be elaborated.

[0039] Both the first passivation film 200 and the second passivation film 600 are passivation films. The passivation film is used to improve the photoelectric conversion efficiency and stability of the solar cell, reduce the surface damage and oxidation reaction of the solar cell, and extend the service life of the solar cell.

[0040] In some possible embodiments, the passivation film includes titanium dioxide, aluminum oxide, iron(III) oxide, etc., without limitation. Preferably, the first passivation film 200 and / or the second passivation film 600 can adopt aluminum oxide to ensure the light absorption rate.

[0041] Optionally, the semiconductor substrate 400 is the base material of the solar cell, such as silicon oxide, a P-type silicon wafer, an N-type silicon wafer, etc., without limitation.

[0042] Optionally, the first conductivity type region 300 and the second conductivity type region 500 may include an emitter region and a back surface field region. Among them, the emitter region refers to the part that extracts electrons from the solar cell. Generally, the emitter region is also regarded as the "positive electrode" of the solar cell. Similarly, the back surface field region is generally an aluminum back surface field in the solar cell. Its main functions include reflecting long waves, reducing light transmission, back surface heavy doping, passivation and gettering, increasing the minority carrier lifetime, and increasing the open circuit voltage, etc. Generally, the back surface field region is also regarded as the "negative electrode" of the solar cell, which will not be elaborated.

[0043] In some embodiments, one of the first conductivity type region 300 and the second conductivity type region 500 is an emitter region, and the other is a back surface field region. In the embodiments of the present application, terms such as first or second are only used to distinguish elements, and the embodiments of the present application are not limited thereto.

[0044] In some possible embodiments, the semiconductor substrate 400 may include a base region, which contains dopants of the first conductivity type with a relatively low doping concentration. The base region may be composed of a crystalline semiconductor containing dopants of the first conductivity type. For example, the base region may include a single crystal or polycrystalline semiconductor (e.g., single crystal silicon or polycrystalline silicon) containing dopants of the first conductivity type. Optionally, the base region may be composed of a single crystal semiconductor (e.g., a single crystal semiconductor wafer, more specifically, a semiconductor silicon wafer) containing dopants of the first conductivity type. Therefore, when the base region is composed of single crystal silicon, the solar cell constitutes a single crystal silicon solar cell. Therefore, the solar cell including a single crystal semiconductor is based on the base region or the semiconductor substrate 400, and has few defects due to excellent crystallinity, and thus exhibits excellent electrical performance.

[0045] Exemplarily, the dopant of the first conductivity type is an n-type or p-type dopant. For example, the dopant of the first conductivity type may be an n-type impurity such as Group V elements (including phosphorus (P), arsenic (As), bismuth (Bi), antimony (Sb), etc.). Or the dopant of the first conductivity type may be a p-type impurity such as Group III elements (including boron (B), aluminum (Al), gallium (Ga), indium (In), etc.).

[0046] Similarly, the base region may include an n-type impurity as the dopant of the first conductivity type, and the emitter region forming a pn junction with the base region is p-type. When light is emitted to the pn junction, the electrons generated by the photovoltaic effect move to the backlight side (e.g., the back surface of the solar cell) of the semiconductor substrate 400 and are collected by the corresponding electrode, and the holes move towards the front surface of the semiconductor substrate 400 and are then collected by the corresponding electrode, thereby generating electric energy. The holes with a low moving speed move towards the front surface of the semiconductor substrate 400, thereby improving the photoelectric conversion efficiency, but the embodiments of the present application are not limited thereto. In other embodiments of the present application, for example, the base region and the back surface field region may be designed as p-type, and the emitter region may be designed as n-type, without limitation.

[0047] In some embodiments, the semiconductor substrate 400 may only include a base region and not include an additional doped region. That is, in a conventional solar cell, a doped region having a conductivity type different from that of the semiconductor substrate 400 or a doped region having the same conductivity type as the semiconductor substrate 400 and a relatively high doping concentration is formed on the semiconductor substrate 400.

[0048] As described above, the semiconductor substrate 400 consists only of the base region and does not include additional doped regions. For example, the difference between the lowest doping concentration and the highest doping concentration in the semiconductor substrate 400 is less than or equal to 10%, such as 9%, 8% or 6%, etc., without limitation.

[0049] The first antireflection film 100 is an antireflection film, also known as an antireflection coating, which is used to reduce or eliminate the reflected light on the optical surfaces such as lenses, prisms, and plane mirrors, thereby increasing the light transmission of these components and reducing or eliminating the stray light in the system.

[0050] Optionally, the first antireflection film 100 may be composed of at least one layer of silicon nitride layer, at least one layer of silicon oxynitride layer, and one layer of silicon oxide layer. In implementation, the at least one layer of silicon nitride layer, the at least one layer of silicon oxynitride layer, and the one layer of silicon oxide layer are sequentially distributed in the direction from close to the semiconductor substrate 400 to away from the semiconductor substrate 400. Exemplarily, taking the first antireflection film 100 as an example, if the first antireflection film 100 is disposed on the front surface of the solar cell and the front surface of the solar cell faces upward, then the at least one layer of silicon nitride layer, the at least one layer of silicon oxynitride layer, and the one layer of silicon oxide layer are sequentially disposed from bottom to top.

[0051] In some embodiments, taking the first antireflection film 100 disposed on the front surface of the solar cell as an example, with the front surface of the solar cell facing upward, the first antireflection film 100 includes one layer of silicon nitride layer, one layer of silicon oxynitride layer, and one layer of silicon oxide layer, and the one layer of silicon nitride layer, the one layer of silicon oxynitride layer, and the one layer of silicon oxide layer are sequentially disposed from bottom to top. For example, a layer of silicon nitride layer is disposed on the upper surface of the first passivation film 200, then a layer of silicon oxynitride layer is disposed on the upper surface of the silicon nitride layer, and then a layer of silicon oxide layer is disposed on the upper surface of the silicon oxynitride layer.

[0052] In some alternative embodiments, two layers of silicon oxynitride layers are disposed between the silicon oxide layer and the silicon nitride layer, that is, the first antireflection film 100 includes one layer of silicon nitride layer, two layers of silicon oxynitride layers, and one layer of silicon oxide layer. For example, still taking the first antireflection film 100 disposed on the front surface of the solar cell as an example, with the front surface of the solar cell facing upward, a layer of silicon nitride layer is disposed on the upper surface of the first passivation film 200, then the first layer of silicon oxynitride layer is disposed on the upper surface of the silicon nitride layer, then the second layer of silicon oxynitride layer is disposed on the upper surface of the first layer of silicon oxynitride layer, and then a layer of silicon oxide layer is disposed on the upper surface of the second layer of silicon oxynitride layer.

[0053] In some possible embodiments, two silicon nitride layers are provided on the side of the silicon oxynitride layer away from the silicon oxide layer, that is, the first antireflection film 100 includes two silicon nitride layers, two silicon oxynitride layers, and one silicon oxide layer. For example, still taking the first antireflection film 100 disposed on the front side of the solar cell as an example, with the front side of the solar cell facing upward, the first silicon nitride layer is disposed on the upper surface of the first passivation film 200, and then the second silicon oxynitride layer is disposed on the upper surface of the first silicon nitride layer. Then, the first silicon oxynitride layer is disposed on the upper surface of the second silicon nitride layer, and then the second silicon oxynitride layer is disposed on the upper surface of the first silicon oxynitride layer. Then, one silicon oxide layer is further disposed on the upper surface of the second silicon oxynitride layer.

[0054] In some possible embodiments, three silicon nitride layers are provided on the side of the silicon oxynitride layer away from the silicon oxide layer, that is, the first antireflection film 100 includes three silicon nitride layers, two silicon oxynitride layers, and one silicon oxide layer. For example, still taking the first antireflection film 100 disposed on the front side of the solar cell as an example, with the front side of the solar cell facing upward, the first silicon nitride layer is disposed on the upper surface of the first passivation film 200, and then the second silicon oxynitride layer is disposed on the upper surface of the first silicon nitride layer. Then, the third silicon oxynitride layer is disposed on the upper surface of the second silicon oxynitride layer. Then, the first silicon oxynitride layer is disposed on the upper surface of the third silicon nitride layer, and then the second silicon oxynitride layer is disposed on the upper surface of the first silicon oxynitride layer. Then, one silicon oxide layer is further disposed on the upper surface of the second silicon oxynitride layer.

[0055] It should be noted that the number of layers of the above-mentioned silicon oxynitride layer and silicon nitride layer is an illustrative example of the embodiments of the present application, rather than a specific limitation on the present application. In some other embodiments, the silicon oxynitride layer and the silicon nitride layer may also adopt other numbers of layers. For example, the number of layers of the silicon oxynitride layer and the silicon nitride layer may be three, four, five or more layers, without limitation.

[0056] The solar cell of the present application includes a first antireflection film 100, a first passivation film 200, a first conductive type region 300, a semiconductor substrate 400, a second conductive type region 500, and a second passivation film 600, which are sequentially arranged from the light-facing side to the backlight side. Among them, the first antireflection film 100 includes at least one silicon nitride layer, at least one silicon oxynitride layer, and one silicon oxide layer. The silicon nitride layer, the silicon oxynitride layer, and the silicon oxide layer are sequentially distributed in the direction from close to the semiconductor substrate 400 to away from the semiconductor substrate 400. Through the above settings, the passivation effect is good, the light reflection can be effectively reduced, the light absorption can be increased, and the power generation efficiency can be improved.

[0057] In some alternative embodiments, an antireflection film is also provided on the back surface of the solar cell provided in the present application, that is, an antireflection film is provided on the side surface of the second passivation film 600 away from the second conductivity type region 500, and the antireflection film on the back surface can be a single-layer film.

[0058] Optionally, the antireflection film on the back surface can be regarded as the second antireflection film 700. Similar to the first antireflection film 100, the second antireflection film 700 can be composed of at least one layer of silicon nitride layer, at least one layer of silicon oxynitride layer, and one layer of silicon oxide layer. Exemplarily, the second antireflection film 700 is provided on the back surface of the solar cell. When the back surface of the solar cell faces downward, at least one layer of silicon nitride layer, at least one layer of silicon oxynitride layer, and one layer of silicon oxide layer of the second antireflection film 700 are sequentially provided from top to bottom.

[0059] When the second antireflection film 700 includes one layer of silicon nitride layer, one layer of silicon oxynitride layer, and one layer of silicon oxide layer, one layer of silicon nitride layer, one layer of silicon oxynitride layer, and one layer of silicon oxide layer are sequentially provided from top to bottom. For example, one layer of silicon nitride layer is provided on the lower surface of the second passivation film 600, then one layer of silicon oxynitride layer is provided on the lower surface of the silicon nitride layer, and then one layer of silicon oxide layer is provided on the lower surface of the silicon oxynitride layer.

[0060] Optionally, when the second antireflection film 700 includes one layer of silicon nitride layer, two layers of silicon oxynitride layer, and one layer of silicon oxide layer, one layer of silicon nitride layer, two layers of silicon oxynitride layer, and one layer of silicon oxide layer are sequentially provided from top to bottom. For example, one layer of silicon nitride layer is provided on the lower surface of the second passivation film 600, then the first layer of silicon oxynitride layer is provided on the lower surface of the silicon nitride layer, then the second layer of silicon oxynitride layer is provided on the lower surface of the first layer of silicon oxynitride layer, and then one layer of silicon oxide layer is provided on the lower surface of the second layer of silicon oxynitride layer.

[0061] Optionally, when the second antireflection film 700 includes two layers of silicon nitride layer, two layers of silicon oxynitride layer, and one layer of silicon oxide layer, two layers of silicon nitride layer, two layers of silicon oxynitride layer, and one layer of silicon oxide layer are sequentially provided from top to bottom. For example, the first layer of silicon nitride layer is provided on the lower surface of the second passivation film 600, then the second layer of silicon oxynitride layer is provided on the lower surface of the first layer of silicon nitride layer, then the first layer of silicon oxynitride layer is provided on the lower surface of the second layer of silicon nitride layer, then the second layer of silicon oxynitride layer is provided on the lower surface of the first layer of silicon oxynitride layer, and then one layer of silicon oxide layer is provided on the lower surface of the second layer of silicon oxynitride layer.

[0062] Optionally, when the second anti-reflection film 700 includes three layers of silicon nitride layers, two layers of silicon oxynitride layers, and one layer of silicon oxide layer, the three layers of silicon nitride layers, two layers of silicon oxynitride layers, and one layer of silicon oxide layer are arranged in sequence from top to bottom. For example, the first layer of silicon nitride layer is disposed on the lower surface of the second passivation film 600, and then the second layer of silicon oxynitride layer is disposed on the lower surface of the first layer of silicon nitride layer, and then the third layer of silicon nitride layer is disposed on the lower surface of the second layer of silicon oxynitride layer, and then the first layer of silicon oxynitride layer is disposed on the lower surface of the third layer of silicon nitride layer, and then the second layer of silicon oxynitride layer is disposed on the lower surface of the first layer of silicon oxynitride layer, and then one layer of silicon oxide layer is further disposed on the lower surface of the second layer of silicon oxynitride layer.

[0063] In some alternative embodiments, the refractive indices of the silicon nitride layer, the silicon oxynitride layer, and the silicon oxide layer decrease in sequence.

[0064] During implementation, the silicon nitride layer is closer to the semiconductor substrate 400 than the silicon oxynitride layer and the silicon oxide layer. At the same time, the refractive index of the silicon nitride layer is higher than the refractive indices of the silicon oxynitride layer and the silicon oxide layer. That is to say, the refractive index of the silicon nitride layer closer to the semiconductor substrate 400 is the highest, the refractive index of the silicon oxynitride layer is lower, and the refractive index of the silicon oxide layer is the lowest. Through the above arrangement, a silicon nitride layer with a high refractive index is disposed in the film layer close to the semiconductor substrate 400. On the one hand, a better passivation effect can be obtained, and at the same time, PID attenuation can be resisted.

[0065] Further, in the direction from close to the semiconductor substrate 400 to away from the semiconductor substrate 400, the refractive indices of the two layers of silicon oxynitride layers decrease in sequence, and the refractive indices of the three layers of silicon nitride layers decrease in sequence.

[0066] The refractive indices between the multiple layers of silicon oxynitride layers are different, and the refractive indices between the multiple layers of silicon nitride layers are also different. The refractive indices of the multiple layers of silicon nitride layers and the multiple layers of silicon oxynitride layers decrease in sequence. Exemplarily, as Figure 4 shown, taking the first anti-reflection film 100 as an example, the first anti-reflection film 100 includes three layers of silicon nitride layers, two layers of silicon oxynitride layers, and one layer of silicon oxide layer. These three layers of silicon nitride layers are SiNx1, SiNx2, and SiNx3 respectively, the two layers of silicon oxynitride layers are SiONx1 and SiONx2 respectively, and one layer of silicon oxide layer is SiOx. Moreover, the layer numbers of SiNx1, SiNx2, SiNx3, SiONx1, SiONx2, and SiOx correspond to L1, L2, L3, L4, L5, and L6 respectively, where L1 is closest to the semiconductor substrate 400, and L6 is the farthest from the semiconductor substrate 400. In such as Figure 4In the illustrated embodiment, the refractive indices of L1, L2, L3, L4, L5, and L6 are 2.25, 2.09, 2.03, 1.70, 1.65, and 1.55 respectively. Designing the film layer near the semiconductor substrate 400 to have a high refractive index can achieve a better passivation effect. However, a high refractive index will cause more light absorption by the film layer, which is not conducive to the light absorption of the semiconductor substrate 400. By designing the silicon nitride and silicon oxynitride layers with different refractive indices as described above, the light absorption of the film layer can be effectively reduced, thereby improving the light absorption of the semiconductor substrate 400.

[0067] The Eta (cell conversion rate), Uoc (open-circuit voltage), Jsc (circuit current density), and FF (fill factor) of the first antireflection film 100 will change with the change in the number of film layers. Generally speaking, they increase as the number of film layers of the first antireflection film 100 increases. Exemplarily, this application shows the data of Eta, Uoc, Jsc, and FF of the first antireflection film 100 including a basic 3-layer film and a 6-layer film, as specifically Figure 5 shown, which will not be elaborated here.

[0068] It should be noted that the refractive indices of L1, L2, L3, L4, L5, and L6 above are examples of an embodiment of this application, rather than specific limitations on this application. In other embodiments, L1, L2, L3, L4, L5, and L6 can also adopt film layers with other refractive indices, as long as the refractive indices of L1, L2, L3, L4, L5, and L6 decrease in sequence, without limitation.

[0069] In some alternative embodiments, the solar cell provided by this application further includes a first tunneling layer 810, and the first tunneling layer 810 is disposed between the first conductive type region 300 and the semiconductor substrate 400.

[0070] During implementation, when photons enter the solar cell, they will excite the electrons on one side and push them towards the tunneling layer. In the tunneling layer, the electrons will pass through the energy bandgap through the tunneling effect and reach the other side. These electrons can generate current or voltage, thereby converting light energy into electrical energy. The tunneling effect improves the efficiency of electron transmission by reducing the height of the energy barrier for electrons to cross, thereby improving the efficiency of the solar cell. That is to say, the role of the tunneling layer is to improve the charge transmission efficiency, that is, to increase the efficiency of the solar cell.

[0071] The first tunneling layer 810 is formed on the front surface of the semiconductor substrate 400. The first tunneling layer 810 passivates the surface of the semiconductor substrate 400 with many recombination sites and facilitates the migration of carriers through the tunneling effect.

[0072] Optionally, the first tunneling layer 810 may include materials that provide passivation and tunneling effects, such as oxides, nitrides, semiconductors, and conductive polymers. For example, the first tunneling layer 810 may include silicon oxide, silicon nitride, silicon oxynitride, intrinsic amorphous silicon, and intrinsic polycrystalline silicon, etc., without limitation.

[0073] Optionally, the solar cell provided by the present application further includes a second tunneling layer 820, which is disposed between the second conductive type region 500 and the semiconductor substrate 400. The second tunneling layer 820 may refer to the above-mentioned first tunneling layer 810, and will not be elaborated here.

[0074] In some possible embodiments, the solar cell further includes a third doping layer 830, which is disposed between the semiconductor substrate 400 and the first tunneling layer 810.

[0075] Furthermore, the solar cell further includes a fourth doping layer 840, which is disposed between the semiconductor substrate 400 and the second tunneling layer 820.

[0076] During implementation, both the third doping layer 830 and the fourth doping layer 840 are doping layers. A doping layer refers to a thin layer of dopants (such as boron, phosphorus, etc.) formed on a solar cell wafer by sputtering or chemical deposition methods, so as to increase the thickness of the effective layer during subsequent epitaxial growth to improve the cell efficiency. The third doping layer 830 and the fourth doping layer 840 have the same doping polarity on the same side. For example, the third doping layer 830 has the same doping type as the first conductive type region 300, and the fourth doping layer 840 has the same doping type as the second conductive type region 400, without elaboration.

[0077] In some possible embodiments, the solar cell provided by the present application further includes a first electrode 910 and a second electrode 920. The first electrode 910 is connected to the first conductive type region 300, and the second electrode 920 is connected to the second conductive type region 500.

[0078] In implementation, the first passivation film 200 and the first antireflection film 100 are both provided with openings. The first electrode 910 is electrically connected to the first conductive type region 300 through the openings formed by the first passivation film 200 and the first antireflection film 100. That is to say, the first electrode 910 passes through the first antireflection film 100 and the first passivation film 200 and then is connected to the first conductive type region 300. Similarly, the second passivation film 600 and the second antireflection film 700 are both provided with openings. The second electrode 920 is electrically connected to the second conductive type region 500 through the openings formed by the second passivation film 600 and the second antireflection film 700. That is to say, the second electrode 920 passes through the second antireflection film 700 and the second passivation film 600 and then is connected to the second conductive type region 500. The first electrode 910 and the second electrode 920 can be formed into various shapes (such as strip-shaped, sheet-shaped or other shapes) by using various conductive materials (such as copper or silver, etc.), which are not limited.

[0079] Embodiment 2

[0080] In some alternative embodiments, the present application further provides a photovoltaic module, including the solar cell as described above.

[0081] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the structure and implementation principle of the photovoltaic module described above can refer to the corresponding structure and implementation principle in the foregoing Embodiment 1, and will not be elaborated herein.

[0082] The solar cell of the present application includes, in sequence from the light-facing side to the backlight side, a first antireflection film 100, a first passivation film 200, a first conductive type region 300, a semiconductor substrate 400, a second conductive type region 500, a second passivation film 600, and a second antireflection film 700. Among them, the first antireflection film 100 and / or the second antireflection film 700 includes at least one silicon nitride layer, at least one silicon oxynitride layer, and one silicon oxide layer. The silicon nitride layer, the silicon oxynitride layer, and the silicon oxide layer are distributed in sequence from the direction close to the semiconductor substrate 400 to the direction away from the semiconductor substrate 400. Through the above settings, the passivation effect is good, the light reflection can be effectively reduced, the light absorption can be increased, and the power generation efficiency can be improved.

[0083] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A solar cell, characterized in that: It includes a first anti-reflection film, a first passivation film, a first conductive type region, a semiconductor substrate, a second conductive type region, and a second passivation film which are sequentially arranged from the light-facing side to the backlight side; The first anti-reflection film includes at least one silicon nitride layer, at least two silicon oxynitride layers and a silicon oxide layer which are sequentially distributed in a direction from close to the semiconductor substrate to far away from the semiconductor substrate.

2. The solar cell according to claim 1, wherein: Three silicon nitride layers are arranged on a side of the silicon oxynitride layer away from the silicon oxide layer.

3. The solar cell according to claim 1, wherein: The refractive indices of the silicon nitride layer, the silicon oxynitride layer, and the silicon oxide layer decrease in sequence.

4. The solar cell according to claim 1, wherein: In a direction from close to the semiconductor substrate to far away from the semiconductor substrate, the refractive indexes of the two silicon oxynitride layers decrease sequentially.

5. The solar cell according to claim 2, characterized in that: In a direction from close to the semiconductor substrate to away from the semiconductor substrate, the refractive indexes of the three silicon nitride layers decrease sequentially.

6. The solar cell according to any one of claims 1 to 5, characterized in that The first anti-reflection film is also disposed on a side of the second passivation film away from the second conductive type region.

7. The solar cell according to claim 1, wherein: The solar cell further includes a first tunneling layer disposed between the first conductive type region and the semiconductor substrate.

8. The solar cell according to claim 7, wherein: The solar cell further includes a second tunneling layer disposed between the second conductive type region and the semiconductor substrate.

9. The solar cell according to claim 7, wherein: The solar cell further includes a third doping layer disposed between the semiconductor substrate and the first tunneling layer.

10. The solar cell according to claim 8, characterized in that The solar cell further includes a fourth doping layer disposed between the semiconductor substrate and the second tunneling layer.

11. The solar cell according to any one of claims 1 to 5, characterized in that The solar cell further includes a first electrode and a second electrode, the first electrode being connected to the first conductive type region, and the second electrode being connected to the second conductive type region.

12. The solar cell according to claim 1, wherein: The first passivation film and / or the second passivation film is aluminum oxide.

13. The solar cell according to claim 8, wherein: The first tunnel layer and the second tunnel layer include at least one of silicon oxide, silicon nitride, silicon oxynitride, intrinsic amorphous silicon, and intrinsic polysilicon.

14. A photovoltaic module, characterized in that: The invention comprises the solar cell according to any one of claims 1 to 13.

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