Solar cell electrode structure

Abstract

The utility model discloses a solar cell electrode structure, which is characterized in that a layer of conductive polymer is printed on an original electrode in a screen printing mode; and the conductive polymer is selected from PEDOT: PSS, Fe2O3 is adjustably added, or polyphenylene sulfide arsenic hexafluoride is selected and AsF5 is adjustably added, so that the conductive polymer layer is blue, the influence of ultraviolet light on a metal electrode can be prevented, the influence of the ultraviolet light on the polymer is relatively small, and in addition, the color integration of the front surface of the battery can be realized.

Description

Technical Field

[0001] This utility model relates to the field of solar cell electrode technology, and in particular to a solar cell electrode structure. Background Technology

[0002] Solar cells have metal electrodes used to collect the current generated by photoelectric conversion and input it into an external circuit. The fabrication method for solar cells with metal electrodes typically involves screen printing a paste onto the front and back of the solar cell.

[0003] The paste used in solar cells contains metal powder, glass, organic carriers, and additives. When solar cells are exposed to ultraviolet (UV) radiation from sunlight for extended periods, the composition and structure of the electrodes change, leading to increased resistance and reduced photoelectric conversion efficiency. Therefore, it is necessary to improve the paste formulation or design new electrode structures to address the problem of increased metal electrode resistance caused by UV radiation.

[0004] Therefore, it is necessary to develop a solar cell electrode structure to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to design a solar cell electrode structure to solve the above-mentioned problems.

[0006] This utility model achieves the above objectives through the following technical solutions:

[0007] A solar cell electrode structure includes a first silicon nitride layer, a second silicon nitride layer, and a first silver electrode, a doped polycrystalline silicon layer, a silicon oxide layer, a silicon substrate, an aluminum oxide layer, and a second silver electrode, which are sequentially connected from one end to the other. The first silicon nitride layer covers the surface of the doped polycrystalline silicon layer, the second silicon nitride layer covers the surface of the aluminum oxide layer, and a conductive polymer layer is disposed on the surface of the second silver electrode.

[0008] As a preferred embodiment, the conductive polymer layer is PEDOT:PSS.

[0009] Furthermore, Fe2O3 is added to the conductive polymer layer.

[0010] As another preferred option, the conductive polymer layer is polyphenylene sulfide arsenic hexafluoride.

[0011] Furthermore, AsF5 is added to the polyphenylene sulfide arsenic hexafluoride.

[0012] Preferably, the conductive polymer layer is disposed on the fine grid of the second silver electrode.

[0013] The beneficial effects of this utility model are as follows:

[0014] This invention involves printing a conductive polymer layer onto the existing electrode. The conductive polymer is PEDOT:PSS, with Fe2O3 added as an option, or polyphenylene sulfide arsenic hexafluoride, with AsF5 added as an option. As a result, the conductive polymer layer is blue, which can prevent the influence of ultraviolet light on the metal electrode. The polymer itself is less affected by ultraviolet light, and it can also achieve a unified color on the front of the battery. Attached Figure Description

[0015] Figure 1 This is a structural schematic diagram (cross-section) of the solar cell electrode structure in this application.

[0016] Figure 2 This is a schematic diagram (top view) of the electrode structure in this application.

[0017] Figure 3 This is a schematic diagram of the fabrication process of the solar cell electrode structure in this application.

[0018] Legend: 1-First silver electrode; 2-First silicon nitride layer; 3-Doped polycrystalline silicon layer; 4-Silicon oxide layer; 5-Silicon substrate; 6-Aluminum oxide layer; 7-Second silicon nitride layer; 8-Second silver electrode; 9-Conductive polymer layer; 10-Main gate; 11-Fine gate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this utility model, it should be understood that the terms "upper", "lower", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use, or the orientation or positional relationship that is commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or component 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 this utility model.

[0023] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0024] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0025] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0026] like Figure 1 As shown, a solar cell electrode structure includes a first silicon nitride layer 2, a second silicon nitride layer 7, and a first silver electrode 1, a doped polycrystalline silicon layer 3, a silicon oxide layer 4, a silicon substrate 5, an aluminum oxide layer 6, and a second silver electrode 8, which are sequentially connected from one end to the other. The first silicon nitride layer 2 covers the surface of the doped polycrystalline silicon layer 3, the second silicon nitride layer 7 covers the surface of the aluminum oxide layer 6, and a conductive polymer layer 9 is disposed on the surface of the second silver electrode 8.

[0027] As a preferred embodiment, the conductive polymer layer is PEDOT:PSS; Fe2O3 is added to the conductive polymer layer.

[0028] As another preferred option, the conductive polymer layer is polyphenylene sulfide arsenic hexafluoride; AsF5 is added to the polyphenylene sulfide arsenic hexafluoride.

[0029] like Figure 2 As shown, in some embodiments, a conductive polymer layer is disposed on the fine gate 11 of the second silver electrode. Printing is only done on the fine gate 11; the main gate 10 of the second silver electrode is not printed because the main gate 10 requires the connection of metal wires, which already shields the underlying main gate from ultraviolet light.

[0030] PEDOT:PSS and polyphenylene sulfide arsenic hexafluoride are both blue conductive liquids that can be deposited onto solids by printing or spraying and cured at high temperatures.

[0031] Coating the metal electrodes of a solar cell with a layer of blue conductive polymer material can prevent the metal electrodes from being exposed to ultraviolet light, and the polymer material itself is minimally affected by ultraviolet radiation. Furthermore, the blue conductive polymer material also has conductive properties, bonding with the metal electrodes and enhancing their conductivity. For PEDOT:PSS, under ultraviolet light irradiation, it increases the bonding between polystyrene sulfonate (PSS) particles, further enhancing conductivity.

[0032] The surface color of solar cells is blue, and they are generally classified into light blue, blue and dark blue according to the depth of the color. The metal electrodes are white. After covering the metal electrodes with blue conductive polymer material, the surface color of the cell can be made uniform and more beautiful. The color depth of the blue conductive polymer can also be adjusted.

[0033] In the traditional solar cell manufacturing process, after screen printing, the cells can be sorted into different colors using automated testing and analysis equipment. This application selects a corresponding blue conductive polymer liquid for printing based on the sorted cells of different colors. Optional blue conductive polymer liquid one: PEDOT:PSS solution. Color configuration: Add an appropriate amount of Fe2O3 to the existing PEDOT:PSS solution to adjust the blue depth. Optional blue conductive polymer liquid two: Polyphenylene sulfide arsenic hexafluoride. Adding an appropriate amount of AsF5 can adjust the blue depth of the liquid, with an adjustable range from blue to black; then the conductive polymer is printed. After printing, annealing at high temperature for a certain time can cure the conductive polymer.

[0034] Apart from this embodiment, this method can also be used on the front electrode of TOPCon cells, PERC cells, and heterojunction cells.

[0035] like Figure 3 As shown, a method for fabricating a solar cell electrode structure includes the following steps:

[0036] S1. Silicon wafer: N-type monocrystalline silicon wafer with a resistivity of 1Ω·cm is selected.

[0037] S2. Rough polishing: Double-sided alkaline polishing is performed using KOH, NaOH or TMAH, reducing the thickness of one side by 2μm;

[0038] S3, Front texturing: The front is texturized with KOH, NaOH or TMAH containing texturing additives, and the front texturing pyramid size is 2um.

[0039] S4, Front-side boron diffusion shallow doping: Boron diffusion is performed on the texturized silicon wafer at high temperature to form a shallow doped region;

[0040] S5. Front-side boron heavy doping: Boron paste is printed on the front side of the silicon wafer according to the electrode pattern, and a mask is printed on the rest of the front side. High-temperature treatment is then used to form a heavily doped region.

[0041] S6. Cleaning: The back side is acid-polished using HF / HNO3, and a water film is evenly covered on the borosilicate glass layer BSG on the front side.

[0042] S7. Preparation of back tunneling oxide layer + doped polycrystalline silicon layer: Tunneling silicon oxide and n-doped amorphous silicon are grown by PECVD, PEALD or PVD, and then annealed to form an n-poly silicon layer.

[0043] S8. Second cleaning: Clean the front borosilicate glass layer and the back phosphosilicate glass layer using HF.

[0044] S9, Front-side alumina deposition: Alumina is deposited on the front side using ALD or PEALD method, with a thickness of 5nm;

[0045] S10, Anti-reflection layer on both front and back: Silicon nitride film, silicon oxynitride film, silicon oxide film, or a combination of films are deposited on the front and back sides as passivation and anti-reflection layers, with a film thickness of 75nm on both sides.

[0046] S11, Printing and Sintering: Print silver paste, align and print silver-aluminum paste or silver paste on the front laser-doped area, print the main grid and fine grid separately on the front, and print the main grid silver paste.

[0047] S12, light injection and laser-assisted sintering.

[0048] S13. Secondary printing: Print a conductive polymer layer on the front of the battery, and anneal it at 100-150℃ for 10-20 minutes after printing.

[0049] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A solar cell electrode structure, characterized by, It includes a first silicon nitride layer, a second silicon nitride layer, and a first silver electrode, a doped polycrystalline silicon layer, a silicon oxide layer, a silicon substrate, an aluminum oxide layer, and a second silver electrode that are sequentially connected from one end to the other. The first silicon nitride layer covers the surface of the doped polycrystalline silicon layer, the second silicon nitride layer covers the surface of the aluminum oxide layer, and a conductive polymer layer is disposed on the surface of the second silver electrode.

2. The solar cell electrode structure according to claim 1, characterized in that, The conductive polymer layer is PEDOT:PSS.

3. A solar cell electrode structure according to claim 1, wherein The conductive polymer layer is polyphenylene sulfide arsenic hexafluoride.

4. A solar cell electrode structure according to claim 1, wherein A conductive polymer layer is disposed on the fine grid of the second silver electrode.

Images