Colorful double-sided crystalline silicon solar cell

Abstract

The utility model discloses a colored double-sided crystalline silicon solar cell which comprises a silicon-based substrate, a plurality of main grid lines and auxiliary grid lines are laid on the back face of the silicon-based substrate, the main grid lines and the auxiliary grid lines are mutually staggered, and the main grid lines and the auxiliary grid lines are electrically connected. A pair of vertically symmetrical inner antireflection film layers and a pair of vertically symmetrical outer antireflection film layers are arranged on the back surface of the silicon-based substrate from inside to outside, the refractive index and the thickness of the outer antireflection film layers are both smaller than those of the inner antireflection film layers, and the difference of the product of the refractive index of the film thickness of the adjacent first antireflection film and second antireflection film is larger than 30%. According to the utility model, the outer reflecting film layer is divided into the upper part and the lower part, the two halves are in mirror symmetry, each half part is provided with the first antireflection film and the second antireflection film with the film thickness refractive index product difference of more than 30%, the film thickness refractive index product difference is the optical path difference, and the difference is more than 30%. Therefore, the two anti-reflection films present different colors.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic cells, in particular to a colored double-sided crystalline silicon solar cell. Background Art

[0002] In the photovoltaic industry, crystalline silicon solar cells occupy an absolute mainstream market position. The types of crystalline silicon solar cells include P-type bifacial PERC cells, N-type bifacial TOPCon cells, N-type bifacial HJT cells, and a small number of full back contact BC cells.

[0003] In the conventional process of preparing solar cells, the anti-reflection film coating process is to coat one or more layers of anti-reflection films with matching optical properties on the surface of the cell. The production of anti-reflection films directly affects the reflectivity of the solar cell to the incident light and plays a very important role in improving the efficiency of the solar cell.

[0004] The back color of the current mainstream bifacial crystalline silicon solar cells is mainly blue. The thickness of the anti-reflection film on the back of the existing bifacial crystalline silicon solar cells is between 75-90nm, and the refractive index is about 2.1. Limited by the film thickness and refractive index, the anti-reflection film basically appears blue, light blue or dark blue. The building-integrated double-glass photovoltaic modules encapsulated by these bifacial crystalline silicon solar cells basically have a dark blue back. When used in building integration, the front of the double-glass photovoltaic module faces outward to receive sunlight, and the back faces inward to the office or residential area of ​​the building. The back color of the photovoltaic module is single, which cannot meet the diverse environmental color requirements of home or office. At the same time, in current large-scale production, only one layer of anti-reflection film is generally coated, which has a low anti-reflection effect and poor passivation, affecting the photoelectric conversion efficiency. Utility Model Content

[0005] The object of the present invention is to provide a colored double-sided crystalline silicon solar cell to solve the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a colored double-sided crystalline silicon solar cell, comprising a silicon-based substrate, a plurality of mutually staggered main grid lines and auxiliary grid lines are laid on the back of the silicon-based substrate, and the main grid lines and the auxiliary grid lines are electrically connected, and a pair of vertically symmetrical inner anti-reflection film layers and a pair of vertically symmetrical outer anti-reflection film layers are arranged on the back of the silicon-based substrate from the inside to the outside, and the refractive index and thickness of the outer anti-reflection film layer are both smaller than those of the inner anti-reflection film layer, and the outer anti-reflection film layer includes a first anti-reflection film and a second anti-reflection film on the same plane, and the difference in the refractive index product of the film thickness of the adjacent first anti-reflection film and the second anti-reflection film is greater than 30%.

[0007] Preferably, the number of the main grid lines is 10 to 20.

[0008] Preferably, the main grid lines and the secondary grid lines are both made of silver.

[0009] Preferably, the first anti-reflection film and the second anti-reflection film are made of one of silicon nitride, silicon oxide, magnesium fluoride, aluminum oxide, and silicon oxynitride.

[0010] Preferably, the spacing between the secondary grid lines is between 1 and 1.5 mm.

[0011] Preferably, the silicon-based substrate is one of a single crystal substrate, a polycrystalline substrate, and a quasi-single crystal substrate.

[0012] The utility model provides a color double-sided crystalline silicon solar cell. It has the following beneficial effects:

[0013] The colored double-sided crystalline silicon solar cell is obtained by dividing the outer reflection film layer into an upper and a lower part, and making the two halves mirror-symmetrical. Each half part has a first anti-reflection film and a second anti-reflection film with a film thickness refractive index product difference of more than 30%. The film thickness refractive index product difference, that is, the difference in optical path difference, is more than 30%, so that the two anti-reflection films present different colors. The double-sided crystalline silicon solar cell with selectable back color enriches the application of environmental color in photovoltaic building integration. At the same time, an inner reflection film layer is added between the outer reflection film layer and the silicon-based substrate, and the refractive index and thickness of the outer reflection film layer are both smaller than those of the inner reflection film layer. The anti-reflection effect of the combination of anti-reflection film layers with different film thicknesses is higher than that of silicon nitride thin films prepared by conventional processes, and the passivation effect of the coating is enhanced, thereby improving the conversion of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of a colored double-sided crystalline silicon solar cell proposed by the utility model;

[0015] Figure 2 A partial cross-sectional view of a colored double-sided crystalline silicon solar cell proposed by the utility model;

[0016] Figure 3 The utility model provides a schematic structural diagram of the outer and inner anti-reflection film layers in a color double-sided crystalline silicon solar cell.

[0017] Legend:

[0018] 1. Silicon-based substrate; 2. Main grid line; 3. Sub-grid line; 4. Inner anti-reflection film layer; 5. Outer anti-reflection film layer; 501. First anti-reflection film; 502. Second anti-reflection film. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0020] Reference Figure 1-3 A color double-sided crystalline silicon solar cell comprises a silicon-based substrate 1, a plurality of mutually interlaced main grid lines 2 and auxiliary grid lines 3 are laid on the back of the silicon-based substrate 1, and the main grid lines 2 and the auxiliary grid lines 3 are electrically connected, the main grid lines 2 and the auxiliary grid lines 3 are both attached to the surface of the cell, the auxiliary grid lines 3 are thinner, and the main grid lines 2 are thicker. After the current is generated, the auxiliary grid lines 3 are used as a passage to collect on the main grid lines 2, and then transmitted to the copper welding belt by the main grid lines 2, and then led out. A pair of symmetrical inner anti-reflection film layers 4 and a pair of symmetrical outer anti-reflection film layers 5 are arranged on the back of the silicon-based substrate 1 from the inside to the outside, and the inner anti-reflection film layer 4 is located at the outer anti-reflection film layer 5. There is an outer anti-reflection film layer 5 between the anti-reflection film layer 5 and the silicon-based substrate 1, and the refractive index and thickness of the outer anti-reflection film layer 5 are smaller than those of the inner anti-reflection film layer 4. The inner anti-reflection film layer 4 and the outer anti-reflection film layer 5 stacked together in a gradient manner have a good passivation effect. Due to their thinner film thickness, the material absorption loss can be reduced. At the same time, the superposition of film layers with different refractive indices can reduce the reflection of light and improve the anti-reflection effect. The outer anti-reflection film layer 5 includes a first anti-reflection film 501 and a second anti-reflection film 502 on the same plane, and the difference in the refractive index product of the film thickness of the adjacent first anti-reflection film 501 and the second anti-reflection film 502 is greater than 30%.

[0021] In a further technical solution of the utility model, the number of main grid lines 2 is 10 to 20. Since the minimum number of main grid lines is ten, the width of each main grid line 2 can be thinner than before, saving the total amount of silver paste and reducing costs. In addition, as the number of main grid lines 2 increases, the distance for the current to flow from the auxiliary grid line 3 to the main grid line 2 becomes shorter, further reducing energy loss.

[0022] In a further technical solution of the present invention, the main grid lines 2 and the auxiliary grid lines 3 are both made of silver, so that the main grid lines 2 and the auxiliary grid lines 3 have excellent electrical conductivity.

[0023] In a further technical solution of the present invention, the first anti-reflection film 501 and the second anti-reflection film 502 are made of one or more of silicon nitride, silicon oxide, magnesium fluoride, aluminum oxide, and silicon oxynitride, and one or more of these materials can be selected to prepare the anti-reflection film according to actual production conditions and needs.

[0024] In a further technical solution of the present invention, the spacing between the auxiliary grid lines 3 is between 1 and 1.5 mm. The smaller spacing can greatly reduce the energy loss caused by the current flowing from the auxiliary grid lines 3 to the main grid lines 2, thereby improving the efficiency of photoelectric conversion.

[0025] In a further technical solution of the present invention, the silicon-based substrate 1 is one of a single crystal substrate, a polycrystalline substrate, and a quasi-single crystal substrate, and any of the above substrates can be selected according to the requirements of actual production and operating environment.

[0026] When the solar cell is irradiated by light, after the internal current is generated, due to the thick main grid line 2, the secondary grid line 3 is used as a passage, and the current is collected on the corresponding main grid line 2, and then transmitted to the copper welding belt by the main grid line 2, and then derived. Since the outer anti-reflection film layer 5 is divided into an upper and lower part, and the two halves are mirror-symmetrical, each half has a first anti-reflection film 501 and a second anti-reflection film 502 with a film thickness refractive index product difference of more than 30%, so that the two anti-reflection films present different colors, such as blue with pink, or blue with green, or gold with pink, etc. This double-sided crystalline silicon solar cell with selectable back color enriches the application of environmental color in photovoltaic building integration. At the same time, an inner anti-reflection film layer 4 is added between the outer anti-reflection film layer 5 and the silicon-based substrate 1, and the refractive index and thickness of the outer anti-reflection film layer 5 are both smaller than those of the inner anti-reflection film layer 4. The anti-reflection effect of this combination of anti-reflection film layers with different film thicknesses is higher than that of silicon nitride thin films prepared by conventional processes, which enhances the passivation effect of the coating, thereby improving the conversion of solar cells.

[0027] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0028] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A color double-sided crystalline silicon solar cell, comprising a silicon-based substrate (1), characterized in that: The back side of the silicon-based substrate (1) is provided with a plurality of mutually interlaced main grid lines (2) and auxiliary grid lines (3), and the main grid lines (2) and the auxiliary grid lines (3) are electrically connected. The back side of the silicon-based substrate (1) is provided with a pair of vertically symmetrical inner anti-reflection film layers (4) and a pair of vertically symmetrical outer anti-reflection film layers (5) from the inside to the outside, and the refractive index and thickness of the outer anti-reflection film layers (5) are both smaller than those of the inner anti-reflection film layers (4); The outer anti-reflection film layer (5) comprises a first anti-reflection film (501) and a second anti-reflection film (502) located on the same plane, and the difference in the film thickness refractive index product of the adjacent first anti-reflection film (501) and the second anti-reflection film (502) is greater than 30%.

2. A color double-sided crystalline silicon solar cell according to claim 1, characterized in that: The number of the main grid lines (2) is 10 to 20.

3. A color double-sided crystalline silicon solar cell according to claim 1, characterized in that: The main grid lines (2) and the auxiliary grid lines (3) are both made of silver.

4. A color double-sided crystalline silicon solar cell according to claim 1, characterized in that: The first anti-reflection film (501) and the second anti-reflection film (502) are made of one of silicon nitride, silicon oxide, magnesium fluoride, aluminum oxide, and silicon oxynitride.

5. A color double-sided crystalline silicon solar cell according to claim 1, characterized in that: The spacing between the auxiliary grid lines (3) is between 1 and 1.5 mm.

6. A color double-sided crystalline silicon solar cell according to claim 1, characterized in that: The silicon-based substrate (1) is one of a single crystal substrate, a polycrystalline substrate and a quasi-single crystal substrate.

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