Photovoltaic cell with light reflecting structure, photovoltaic module and photovoltaic system

Abstract

The application relates to the field of photoelectric technology, in particular to a photovoltaic cell with a light reflection structure, a photovoltaic module and a system, the photovoltaic cell comprising a semiconductor substrate for absorbing light energy and generating current; a fine-grid metal conductive electrode arranged on the surface of the semiconductor substrate for collecting the current on the surface of the semiconductor substrate; a main-grid metal wire connected with the fine-grid metal conductive electrode perpendicularly for collecting the current on the fine-grid metal conductive electrode and outputting; and a plurality of metal reflection layers for reflecting the light energy penetrating through the semiconductor substrate to the semiconductor substrate, wherein the metal reflection layers only cover the areas between the fine-grid metal conductive electrodes. The application forms a basis for the action of light energy through the semiconductor substrate, the fine-grid metal conductive electrode and the main-grid metal wire, so that the light energy penetrating through the semiconductor substrate can be reflected back to the semiconductor substrate after reaching the metal reflection layers, thereby realizing the full utilization of the light energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optoelectronic technology, and in particular to a photovoltaic cell with light reflection structure. BACKGROUND

[0002] The optoelectronic technology industry is experiencing unprecedented growth worldwide, especially in China, with strong growth in market size and technological innovation. Photovoltaic cells, also known as solar cells, are devices that can directly convert solar energy into electrical energy.

[0003] The patent document with publication number CN117976776A discloses a battery piece, which includes a single crystal silicon layer, one side of the single crystal silicon layer has a textured structure layer, the other side of the single crystal silicon layer has a polishing structure layer, and the preparation method adopted includes polishing and cleaning the semiconductor substrate; the first surface of the semiconductor substrate is subjected to oxidation treatment to form an oxide film on the first surface; the second surface of the semiconductor substrate is subjected to phosphorus source treatment to purify impurities in the semiconductor substrate; the semiconductor substrate is subjected to texturing operation to form a polishing structure layer on the first surface under the isolation of the oxide film, and a structure layer different from the first surface is formed on the second surface of the semiconductor substrate; the impurities and the oxide film on the semiconductor substrate are removed by acid washing; a silicon layer is deposited on the first surface and the second surface of the semiconductor substrate; a transparent conductive film layer is deposited on the silicon layer of the semiconductor substrate, and then printing and curing are performed to obtain a battery piece.

[0004] However, the battery piece in the prior art is to treat the first surface of the semiconductor substrate to form a polishing structure layer, which is directly applied to the semiconductor substrate, and the operation difficulty is great, and the contact area between the printed electrode and the surface of the semiconductor substrate is reduced, thereby reducing the current collection efficiency. SUMMARY

[0005] Therefore, the present application provides a photovoltaic cell with light reflection structure, which can make the transmitted light re-enter the battery piece by setting a metal reflection layer, improve the utilization rate of light energy, and greatly improve the current collection efficiency due to the large contact area between the electrode and the semiconductor substrate.

[0006] To achieve the above-mentioned purpose, the present application provides a photovoltaic cell with light reflection structure, which includes:

[0007] a semiconductor substrate for absorbing light energy and generating current;

[0008] a plurality of fine grid metal conductive electrodes arranged in parallel on the surface of the semiconductor substrate for collecting current on the surface of the semiconductor substrate;

[0009] a metal reflective layer for reflecting light energy passing through the semiconductor substrate to the semiconductor substrate, the metal reflective layer covering the area between the fine grid metal conductive electrodes;

[0010] the semiconductor substrate has a first surface, the first surface being close to the metal reflective layer, the area of the metal reflective layer in the orthographic projection of the semiconductor substrate being the area of the first surface of the semiconductor substrate minus the area of the fine grid metal conductive electrodes in the orthographic projection of the semiconductor substrate.

[0011] Further, the application further comprises a main grid metal wire connected to the fine grid metal conductive electrodes for collecting and outputting the current on the fine grid metal conductive electrodes, a plurality of fine grid metal conductive electrodes being arranged between any two adjacent main grid metal wires, the metal reflective layer not covering the main grid metal wire, the arrangement density of the fine grid metal conductive electrodes being greater than that of the main grid metal wire.

[0012] Further, the application further comprises a transparent conductive film layer for conducting the current generated by the semiconductor substrate.

[0013] Further, the transparent conductive film layer is an ITO film, and the material of the fine grid metal conductive electrodes and the main grid metal wire is a metal element or a metal alloy.

[0014] Further, the metal reflective layer is an aluminum layer, a silver layer, a nickel layer or a metal alloy layer.

[0015] Further, the application further comprises a magnesium fluoride layer for cooperating with the metal reflective layer to form a multi-medium reflective film.

[0016] Further, the metal reflective layer is single-sided reflective, and the reflective surface of the metal reflective layer is arranged on the side close to the semiconductor substrate.

[0017] Further, the thickness of the semiconductor substrate is between 70mm and 250mm.

[0018] In a second aspect, the application further provides a photovoltaic module comprising photovoltaic cells with light reflective structures, and the adjacent photovoltaic cells are electrically connected by main grid metal wires.

[0019] In a third aspect, the application further provides a photovoltaic system comprising the photovoltaic module.

[0020] Compared with the prior art, the beneficial effects of the present application are that the semiconductor substrate, the fine-grid metal conductive electrode and the main-grid metal conductive wire form the basis for the action of light energy, and in practical application, the light enters the semiconductor substrate to excite the electrons in the semiconductor substrate, and because the actual thickness of the semiconductor substrate is small, the light is relatively easy to penetrate, so the metal reflective layer arranged on the other surface of the semiconductor substrate is arranged close to the side of the semiconductor substrate to reflect, so that the light energy that has passed through the semiconductor substrate can be reflected back to the semiconductor substrate after reaching the metal reflective layer, thereby achieving full utilization of the light energy, effectively exciting the electrons in the semiconductor substrate, and thereby generating more electric energy that is collected by the fine-grid metal conductive electrode, thereby improving the utilization efficiency of light energy.

[0021] In particular, the grid layer structure can realize the flow guiding effect and effectively collect the current formed on the surface of the semiconductor substrate, and because the copper wire and the aluminum wire have good conductivity, the current formed by the directional movement of the electrons excited by the light energy on the surface of the semiconductor substrate can be effectively collected, and in the embodiment of the present application, the grid layer structure not only serves as the basis for arranging the metal reflective layer, but also serves as the conductive electrode, thereby greatly saving the preparation raw materials and effectively reducing the manufacturing cost.

[0022] In particular, the fine-grid metal conductive electrode is distributed between the main-grid metal conductive wires, so that the current generated by the photoelectrons on the surface of the cell piece can be collected more quickly, the transmission distance of the current on the fine-grid metal conductive electrode is shortened, thereby reducing the loss of the current in the transmission process, and the fine-grid metal conductive electrode arranged on the back surface of the semiconductor substrate covers part of the area on the surface of the cell piece, so that the photoelectric current can be more fully collected, thereby improving the photoelectric conversion efficiency of the cell piece. Because the fine-grid metal conductive electrode makes the current transmission path shorter, the resistance loss of the current on the fine-grid metal conductive electrode is relatively small, thereby improving the overall efficiency of the cell piece, the fine-grid metal conductive electrode is usually made of a metal material with high conductivity, which can effectively transmit the current from the surface of the cell piece to the main-grid metal conductive wire, thereby further reducing the resistance loss. In the technology without the main-grid metal conductive wire, the metal wire is used to realize the connection of the cell piece, and after the number of main-grid metal conductive wires is increased, the fine-grid metal conductive electrode can be made thinner, so that the use of high-cost materials such as silver paste can be reduced, thereby reducing the manufacturing cost of the cell piece. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 FIG. 1 is a schematic view of the side structure of a photovoltaic cell with a light reflection structure in an embodiment of the present application;

[0024] Figure 2 FIG. 3 is a schematic view of the grid layer structure in the photovoltaic cell with the light reflection structure in the embodiment of the present application;

[0025] Figure 3A schematic diagram of a planar structure of a photovoltaic cell with light reflection structure in the embodiments of the present application.

[0026] Reference signs:

[0027] 1, semiconductor substrate; 2, main grid metal wire; 3, metal reflection layer; 4, fine grid metal conductive electrode; 5, transparent conductive film layer. DETAILED DESCRIPTION

[0028] In order to make the objects and advantages of the present application more clear, the present application will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0029] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present application, and are not used to limit the protection scope of the present application.

[0030] It should be noted that, in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the direction or positional relationship terms based on the direction or positional relationship shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0031] In addition, it should also be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] Please refer to Figure 1 The photovoltaic cell with light reflection structure provided by the embodiments of the present application comprises:

[0033] The semiconductor substrate 1 is used to absorb light energy and generate current;

[0034] The fine grid metal conductive electrode 4 is arranged in parallel on the surface of the semiconductor substrate, and is used to collect the current on the surface of the semiconductor substrate;

[0035] The main grid metal wire 2 is connected with the fine grid metal conductive electrode, and is used for collecting the current on the fine grid metal conductive electrode and outputting. A plurality of fine grid metal conductive electrodes are arranged between any two adjacent main grid metal wires. The metal reflective layer does not cover the main grid metal wire. The arrangement density of the fine grid metal conductive electrode is greater than that of the main grid metal wire.

[0036] A plurality of metal reflective layers 3 are used for reflecting the light energy penetrating through the semiconductor substrate to the semiconductor substrate. The metal reflective layer covers the area between the fine grid metal conductive electrodes.

[0037] The semiconductor substrate has a first surface, and the first surface is close to the metal reflective layer. The area of the metal reflective layer in the orthographic projection of the semiconductor substrate is the area of the first surface of the semiconductor substrate minus the area of the fine grid metal conductive electrode and the main grid metal wire in the orthographic projection of the semiconductor substrate.

[0038] In particular, the photovoltaic cell with the light reflection structure provided by the embodiment of the present application comprises a semiconductor substrate, a grid structure layer and a metal reflective layer. In actual application, the two surfaces of the semiconductor substrate are provided with the grid structure layer. The semiconductor substrate can also be provided with a layer structure on the surface. Other arrangement modes can also be adopted, which are not listed one by one. The grid structure layer is used for collecting the current on the surface of the semiconductor substrate and outputting, so as to ensure the efficient collection of the current on the surface of the semiconductor substrate. The grid structure layer comprises a main grid metal wire and a fine grid metal conductive electrode. In actual preparation process, the main grid metal wire is usually printed on the surface of the semiconductor substrate, and then the fine grid metal conductive electrode is printed. The fine grid metal conductive electrode is overlapped on the main grid metal wire. Generally, the fine grid metal conductive electrode has a large arrangement density, which can maximize the collection of the current formed on the surface of the semiconductor substrate due to the light energy. However, the density that is too large will affect the area of the metal reflective layer, so that the area of the metal reflective layer is reduced, and the reflected light is reduced. Therefore, the density of the fine grid metal conductive electrode in the embodiment of the present application cannot be too large. The problems of the reflection area and the collection efficiency need to be considered. The metal reflective layer is arranged on the side of the grid structure layer away from the semiconductor substrate. The metal reflective layer covers the area between the fine grid metal conductive electrodes, so that the main grid metal wire can be electrically connected with other main grid metal wires, thereby forming a cell string, and the photovoltaic power generation is greatly improved. In addition, by arranging the metal reflective layer on the first surface of the semiconductor substrate and ensuring that the area of the metal reflective layer in the orthographic projection of the semiconductor substrate is the area of the first surface of the semiconductor substrate minus the area of the fine grid metal conductive electrode and the main grid metal wire in the orthographic projection of the semiconductor substrate, the metal reflective layer basically covers the semiconductor substrate. The light projection loss can be effectively reduced, the light can be reflected back into the semiconductor substrate as much as possible, the propagation path of the light in the semiconductor substrate is increased, the light absorption rate is improved, and the photoelectric conversion efficiency of the photovoltaic cell is improved. In the embodiment of the present application, the first surface can be the back surface of the semiconductor substrate.

[0039] In an alternative embodiment, the upper and lower surfaces of the semiconductor substrate are provided with a grid structure layer, the metal reflective layer is arranged on the side of the grid structure layer away from the semiconductor substrate, the side of the metal reflective layer close to the semiconductor substrate is used for reflection, and the side of the metal reflective layer away from the semiconductor substrate is capable of transmitting light, so that light can pass through the metal reflective layer, the grid structure layer and reach the semiconductor substrate, thereby exciting the state of the electrons in the semiconductor substrate, and then moving directionally to form an electric current.

[0040] In another alternative embodiment, one surface of the semiconductor substrate is provided with a grid layer structure, the grid layer structure includes a vertical fine grid metal conductive electrode and a main grid metal wire, wherein the fine grid metal conductive electrode and the main grid metal wire are arranged on one surface of the semiconductor substrate, and the fine grid metal conductive electrode and the main grid metal wire are connected to a negative electrode and a positive electrode respectively, thereby achieving the export of the current on the surface of the semiconductor substrate, by arranging a metal reflective layer on the semiconductor substrate, and the metal reflective layer does not cover the grid layer structure, so that the light entering from the other surface of the semiconductor substrate can return to the semiconductor substrate under the action of the metal reflective layer after transmitting out of the semiconductor substrate, thereby realizing the reuse of light, improving the excitation of light on the electrons in the semiconductor substrate, and improving the light utilization efficiency.

[0041] Specifically, the semiconductor substrate, the fine grid metal conductive electrode and the main grid metal wire form the basis for the action of light energy in practical application, because the light enters the semiconductor substrate to excite the electrons in the semiconductor substrate, and because the actual thickness of the semiconductor substrate is small, the light is relatively easy to penetrate, so the metal reflective layer arranged on the other surface of the semiconductor substrate is close to the semiconductor substrate for reflection, so that the light passing through the semiconductor substrate can be reflected back to the semiconductor substrate after reaching the metal reflective layer, thereby realizing the full use of light energy, effectively exciting the electrons in the semiconductor substrate, and then generating more electric energy which is collected by the fine grid metal conductive electrode, thereby improving the light energy utilization efficiency.

[0042] Specifically, the material of the fine grid metal conductive electrode and the main grid metal wire is a metal element or a metal alloy.

[0043] Specifically, in an alternative embodiment of the present application, the photovoltaic cell with light reflection structure comprises a semiconductor substrate, a grid layer structure is arranged on both sides of the semiconductor substrate, the main grid metal wire in the grid layer structure is a copper wire, the fine grid metal conductive electrode is an aluminum wire, other metal wire or conductive paste, which is not limited herein, and a metal reflection layer covering the aluminum wire, the metal reflection layer covers the fine grid metal conductive electrode of the aluminum wire material, so that the grid layer structure can realize the flow guiding effect and effectively collect the current formed on the surface of the semiconductor substrate, due to the good conductivity of the copper wire and the aluminum wire, the current formed by the directional movement of the electrons excited on the surface of the semiconductor substrate due to the action of light energy can be effectively collected, and in the embodiment of the present application, the grid layer structure not only can serve as the basis for arranging the metal reflection layer, but also can serve as the conductive electrode, thereby greatly saving the preparation raw materials and effectively reducing the production cost.

[0044] In actual application process, when the sunlight passes through the grid layer structure arranged on the first surface of the semiconductor substrate, the sunlight acts on the semiconductor substrate to excite the electrons in the semiconductor substrate to be in an excited state, the electrons in the excited state are unstable, and once they move directionally, current can be generated, but since the thickness of the semiconductor substrate is small, the sunlight can directly pass through the semiconductor substrate, so that the sunlight cannot fully act on the semiconductor substrate, and thus fewer electrons are generated, but since the metal reflection layer is arranged on the grid layer structure arranged on the second surface of the semiconductor substrate, the transmitted sunlight can be reflected by the metal reflection layer again, and then return to the semiconductor substrate again, and act on the semiconductor substrate again, when the sunlight acts on the semiconductor substrate and then emits from the semiconductor substrate, the metal reflection layer can be arranged on the side of the grid layer structure arranged on the first surface of the semiconductor substrate close to the semiconductor substrate, so that the metal reflection layer is arranged on the upper and lower surfaces of the semiconductor substrate, so that the sunlight can be captured by the semiconductor substrate, and the sunlight can be fully utilized to excite the electrons in the semiconductor substrate, so that more electric energy is generated and guided by the grid layer structure, thereby effectively improving the utilization efficiency of the sunlight.

[0045] Specifically, a transparent conductive film layer 5 is further arranged to guide the current generated by the semiconductor substrate. The transparent conductive film layer is an ITO film. The metal reflection layer is single-sided reflection, and the reflection surface of the metal reflection layer is arranged on the side close to the semiconductor substrate.

[0046] Specifically, the ITO film in the embodiment of the present application can serve as the substrate of the grid layer structure, due to the transparent property, the light can pass through the semiconductor substrate, and the function of collecting and transmitting electrons can also be realized, thereby improving the utilization efficiency of the sunlight.

[0047] Specifically, in another alternative embodiment of the present application, the photovoltaic cell with light reflection structure comprises a semiconductor substrate, an ITO film, a grid layer structure, and a metal reflection layer, wherein the ITO film is arranged on one side of the fine grid metal conductive electrode close to the semiconductor substrate, the ITO film is close to the semiconductor substrate, the ITO film is uniformly and closely arranged on the surface of the semiconductor substrate, and can capture all the electrons on the surface of the semiconductor substrate. In actual application, the metal reflection layer is single-sided reflection, which can transmit sunlight into the grid layer structure and the ITO film to reach the semiconductor substrate, and after the sunlight penetrates the semiconductor substrate, the sunlight can still be utilized by the semiconductor substrate through the ITO film again by using the metal reflection layer with single-sided reflection film structure, thereby effectively improving the transmittance of sunlight and the utilization efficiency of sunlight.

[0048] Specifically, the photovoltaic cell with light reflection structure in the embodiment of the present application further comprises a magnesium fluoride layer, which cooperates with the metal reflection layer to form a multi-medium reflection film.

[0049] Specifically, in actual application, the magnesium fluoride layer and the metal reflection layer are arranged adjacent to each other to form a multi-medium reflection film. When the sunlight penetrates the semiconductor substrate and enters the multi-medium reflection film formed by the magnesium fluoride layer and the metal reflection layer, the refractive index of the magnesium fluoride is less than that of the metal reflection layer, and thus a reflection is formed at the interface between the two, so that the sunlight reenters the semiconductor substrate, thereby realizing effective utilization of light energy.

[0050] Specifically, by arranging the magnesium fluoride layer and the metal reflection layer adjacent to each other to form a multi-medium reflection film, the light emitted from the semiconductor substrate enters the magnesium fluoride layer, and at this time a reflection interface is formed at the interface between the magnesium fluoride layer and the metal reflection layer, so that the light can be reflected back to the semiconductor substrate. This structure design can increase the propagation path of light in the cell, thereby improving the light absorption rate and further improving the photoelectric conversion efficiency of the cell.

[0051] Specifically, the metal reflection layer is an aluminum layer, a silver layer, a nickel layer, or a metal alloy layer.

[0052] Specifically, in actual application, the metal reflection layer can be an aluminum layer, a silver layer, or a nickel layer, as long as it can reflect, and preferably an aluminum layer is used as the metal reflection layer, which can save costs.

[0053] Specifically, a plurality of fine grid metal conductive electrodes are arranged between any two adjacent main grid metal wires.

[0054] Specifically, the fine-grid metal conductive electrode is distributed between the main-grid metal conductive wires, so that the current generated by photo-generated electrons on the surface of the cell sheet can be collected more quickly, the distance of current conduction on the fine-grid metal conductive electrode is shortened, thereby reducing the loss of current in the transmission process. The fine-grid metal conductive electrode covers part of the area of the surface of the cell sheet, so that the photo-generated current can be more fully collected, and the photoelectric conversion efficiency of the cell sheet is improved. Because the fine-grid metal conductive electrode makes the current transmission path shorter, the resistance loss of the current on the fine-grid metal conductive electrode is relatively small, the overall efficiency of the cell sheet is improved, and the fine-grid metal conductive electrode is usually made of a high-conductivity metal material, which can effectively transmit the current from the surface of the cell sheet to the main-grid metal conductive wire, further reducing the resistance loss. In the multi-main-grid metal conductive wire technology, the number of main-grid metal conductive wires increases, and the fine-grid metal conductive electrode can be made thinner, which can reduce the use of high-cost materials such as silver paste, thereby reducing the manufacturing cost of the cell sheet.

[0055] Specifically, the thickness of the semiconductor substrate is between 70mm-250mm.

[0056] Specifically, the thickness of the semiconductor substrate affects its heat conduction performance. A thicker semiconductor substrate can better conduct the heat generated by the device to the heat dissipation system, thereby improving the heat management efficiency, ensuring the stable operation of the device in a high temperature environment, and effectively reducing the thermal resistance between the semiconductor substrate and the heat sink by reasonably setting the thickness of the semiconductor substrate, so that heat is more easily conducted from the semiconductor substrate to the heat sink, further improving the heat dissipation effect. The thickness of the semiconductor substrate is set to be between 70mm-250mm in order to comprehensively consider mechanical strength, heat management, electrical performance, manufacturing process compatibility, cost and benefit balance and other factors to meet the needs of different application scenarios and ensure the performance and reliability of the semiconductor device.

[0057] Embodiment one

[0058] The photovoltaic cell with the light reflection structure provided by the embodiment of the present application comprises a semiconductor substrate, a grid structure layer and a metal reflection layer, wherein the metal reflection layer is arranged between the semiconductor substrate and the grid structure layer, the metal reflection layer is arranged on the side of the grid structure layer close to the semiconductor substrate, and the metal reflection layer covers the fine-grid metal conductive electrodes of the grid structure layer and the area between the fine-grid metal conductive electrodes. The structure design aims to improve the light utilization rate and reduce the reflection loss of light, thereby improving the photoelectric conversion efficiency. Generally, in actual application, an ITO film for absorbing photoelectrons is further arranged between the semiconductor substrate and the grid structure layer, wherein the high transmittance and low reflectance characteristics of the ITO film ensure that more light can enter the semiconductor substrate and be absorbed, and the scattering and reflection loss of light is reduced. By optimizing the preparation process of the ITO film, the resistivity of the ITO film can be reduced, the series resistance can be reduced, and the current transmission efficiency can be improved, thereby improving the electrical performance of the cell sheet. By optimizing the light reflection structure, the photoelectric conversion efficiency, stability and environmental adaptability of the photovoltaic cell are significantly improved, and the production cost is reduced. The structure design is not only suitable for various cell sheet forms, but also is universal for the construction of high-efficiency laminated cells.

[0059] Embodiment two

[0060] The photovoltaic cell with the light reflection structure provided by the embodiment of the present application comprises a semiconductor substrate, a grid structure layer, a first metal reflection layer, an ITO film and a second metal reflection layer, wherein the ITO film is arranged between the semiconductor substrate and the grid structure layer, the first metal reflection layer is arranged on the side of the grid structure layer close to the semiconductor substrate, and the second metal reflection layer is arranged on the side of the ITO film close to the grid structure layer. The first metal reflection layer and the second metal reflection layer are both single-sided reflection layers, and through the multi-layer film structure, high light transmittance can be realized on one side, and high reflectivity can be realized on the other side. For example, based on the film structure of fluorine-doped tin oxide / silver / fluorine-doped tin oxide, high transmittance (average transmittance 82.52%) can be realized in the visible light band, and high reflectivity (average reflectance 81.46%) can be realized in the infrared band, thereby meeting the requirements of light transmission on one side and light reflection on the other side. The first metal reflection layer and the second metal reflection layer reflect the light transmitted out of the cell sheet back into the cell sheet, increasing the multiple reflection and absorption opportunities of light in the cell sheet, thereby improving the light utilization rate, and further increasing the current formed on the surface of the cell sheet and improving the photoelectric conversion efficiency. The present application is suitable for various cell sheet forms, including the cell sheet in the prior art, the cell sheet comprising a grid structure layer and the cell sheet comprising only fine-grid metal conductive electrodes, and has wide applicability. The embodiment of the present application is not only suitable for single-junction cells, but also suitable for cell strings, and can realize higher photoelectric conversion efficiency. By optimizing the light reflection structure, the photoelectric conversion efficiency, stability and environmental adaptability of the photovoltaic cell are significantly improved, and the production cost is reduced.

[0061] Embodiment three

[0062] The photovoltaic cell with the light reflection structure provided by the embodiment of the present application comprises a semiconductor substrate, an ITO film and a metal reflection layer, and the metal reflection layer is arranged on the side of the ITO film close to the semiconductor substrate. The metal reflection layer is plated behind the ITO film by vacuum plating, such as thermal evaporation or magnetron sputtering. The two methods are mainly used to form a reflection surface on the ITO film to return the light transmitted through the semiconductor substrate, so that the light can be reflected and then absorbed by the semiconductor substrate again, thereby improving the light utilization efficiency. The semiconductor substrate can be a silicon substrate, and the metal reflection layer can also realize the current conduction function, which can be regarded as a fine grid metal conductive electrode to realize the collection and conduction of the current on the semiconductor substrate and improve the light energy utilization efficiency.

[0063] In actual application, the components on both sides of the semiconductor substrate are arranged in mirror symmetry with the semiconductor substrate as the center, so that the semiconductor substrate can be reflected between the two metal reflection layers, thereby improving the light energy utilization efficiency.

[0064] The embodiment of the present application also provides a photovoltaic module comprising the photovoltaic cell with the light reflection structure, and the adjacent photovoltaic cells are electrically connected by the main grid metal wires.

[0065] Specifically, in the actual preparation process, the metal reflection layer covers the fine grid metal conductive electrode and the area therebetween, and the main grid metal wires are reserved because the main grid metal wires need to be connected in series during the electrical connection. Generally, the metal reflection layer can be plated after the positions of the main grid metal wires are reserved, and the fine grid metal conductive electrodes for collecting photo-generated electrons are made on the front and back surfaces of the cell sheet, so that the front and back surfaces of the cell sheet form a plurality of fine grid metal conductive electrodes arranged uniformly. The fine grid metal conductive electrodes are arranged perpendicularly to the main grid metal wires. In the specific implementation process, a plurality of main grid metal wires capable of converging the fine grid metal conductive electrodes and conducting the fine grid metal conductive electrodes out of the cell sheet are formed by hot pressing.

[0066] Specifically, the photovoltaic module provided by the embodiment of the present application is provided with fine-grid metal conductive electrodes for collecting photo-generated electrons on the front and back surfaces of the cell, and the fine grids are arranged perpendicularly to the main grids, which can more effectively collect photo-generated carriers and reduce the recombination of the carriers, thereby improving the photoelectric conversion efficiency of the cell. The main grid metal wires are formed by electrical connection, which can reduce the resistance of the main grid and reduce the loss of current in the transmission process compared with the traditional printed main grid, thereby further improving the output power of the cell. The metal reflective layer covers the fine-grid metal conductive electrodes, which can protect the fine grids from being damaged in the subsequent process and improve the stability and reliability of the cell. On the premise of retaining the main grid metal wires, the complexity of the electrode structure of the cell is reduced by reasonable design and process, so that the overall structure of the cell is more simple, which is conducive to improving the production efficiency and quality control of the cell. The fine-grid metal conductive electrodes and the main grid metal wires are combined, which can significantly reduce the amount of silver paste compared with the traditional full-silver paste printed electrode, thereby reducing the production cost of the cell. The position of the main grid metal wires is left out after the metal reflective layer is plated, and this precise process control can improve the utilization rate of materials and reduce material waste, thereby further reducing the cost. The preparation of the metal reflective layer is combined with the formation of the electrode, which reduces part of the process steps, so that the production process of the entire cell is more simple and efficient, which is helpful to improve the production efficiency. The process of hot pressing the metal wires to form the main grid metal wires is easy to realize automatic operation, which can improve the consistency and stability of production, adapt to the demand of large-scale automatic production, and further improve the production efficiency.

[0067] The embodiment of the present application also provides a photovoltaic system comprising the photovoltaic module.

[0068] The photovoltaic system in the embodiment of the present application comprises the photovoltaic module and can achieve the same technical effects, which will not be described here.

[0069] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.

[0070] The above description is only the preferred embodiments of the present application and is not used to limit the present application; for those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A photovoltaic cell having a light-reflecting structure, characterized by, The application relates to a photovoltaic cell with a light reflection structure. The photovoltaic cell comprises: a semiconductor substrate for absorbing light energy and generating electric current; a plurality of fine-grid metal conductive electrodes arranged in parallel on the surface of the semiconductor substrate for collecting the electric current on the surface of the semiconductor substrate; a metal reflection layer for reflecting the light energy that has penetrated through the semiconductor substrate to the semiconductor substrate, the metal reflection layer covering the area between the fine-grid metal conductive electrodes; the semiconductor substrate has a first surface, the first surface being close to the metal reflection layer, the area of the orthographic projection of the metal reflection layer on the semiconductor substrate being the area of the first surface of the semiconductor substrate minus the area of the orthographic projection of the fine-grid metal conductive electrodes and the main-grid metal wires on the semiconductor substrate; the main-grid metal wires are connected with the fine-grid metal conductive electrodes for collecting the electric current on the fine-grid metal conductive electrodes and outputting, a plurality of the fine-grid metal conductive electrodes being arranged between any two adjacent main-grid metal wires, the metal reflection layer not covering the main-grid metal wires, and the arrangement density of the fine-grid metal conductive electrodes being greater than the arrangement density of the main-grid metal wires; the photovoltaic cell further comprises a transparent conductive film layer for leading out the electric current generated by the semiconductor substrate; 2. The photovoltaic cell with light reflecting structure according to claim 1, characterized in that, the photovoltaic cell further comprises a magnesium fluoride layer for jointly forming a multi-medium reflection film with the metal reflection layer.

3. The photovoltaic cell with light reflecting structures according to claim 1 or 2, characterized in that, The transparent conductive film layer is an ITO film, and the material of the fine-grid metal conductive electrodes and the main-grid metal wires is a metal element or a metal alloy.

4. The photovoltaic cell with light reflecting structures according to claim 1, characterized in that, The metal reflection layer is an aluminum layer, a silver layer, a nickel layer or a metal alloy layer.

5. The photovoltaic cell with light reflecting structures according to claim 1, characterized in that, The metal reflection layer is single-sided reflection, and the reflection surface of the metal reflection layer is arranged on the side close to the semiconductor substrate.

6. A photovoltaic module, characterized by The thickness of the semiconductor substrate is between 70 mm and 250 mm.

7. A photovoltaic system characterized by, The application further relates to a photovoltaic module comprising the photovoltaic cell with the light reflection structure as claimed in any one of claims 1 to 5, and the main-grid metal wires are used for electrically connecting the adjacent photovoltaic cells. The application further relates to a photovoltaic module comprising the photovoltaic cell as claimed in claim 6.

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