Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module, the solar cell comprises a silicon wafer and an anti-reflection structure arranged on the surface of the silicon wafer, and the anti-reflection structure comprises a first anti-reflection layer arranged on the surface of the silicon wafer and a second anti-reflection layer arranged on the surface of the first anti-reflection layer. The refractive index of the first anti-reflection layer is n1, the refractive index of the second anti-reflection layer is n2, and n1 and n2 meet one of the following relationships: (a) n2-n1 is more than or equal to-0.4 and less than or equal to-0.05; (b) 0.1 < = n2-n1 < = 0.4. Based on the design of the double-anti-reflection layer structure and the fact that the difference value of the refractive indexes of the double-anti-reflection layer structure and the double-anti-reflection layer structure is set in the range, the whole double-anti-reflection layer structure has a strong color modulation effect, and when the thickness of the edge and the thickness of the center of the cell have a certain difference, the color of the edge and the center of the cell are kept consistent in a wide thickness range. The color of the sticking point area is consistent with the color of other areas in a wide thickness range, so that a blue edge phenomenon and sticking point marks can be weakened and even completely covered, and the surface color uniformity and attractiveness of the solar cell are improved.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic power generation technology, and in particular, relates to a solar cell and a photovoltaic module. Background Art

[0002] A thin film with a reduced reflectivity is usually disposed on the surface of a solar cell. The thin film is called an anti-reflective coating. The anti-reflective coating can reduce the reflectivity of the solar cell and improve the efficiency of the cell.

[0003] At present, common solutions for anti-reflection layers include velvet structure anti-reflection and / or anti-reflection film anti-reflection. For example, the pyramid velvet structure achieves anti-reflection by changing the surface structure and the light path; a silicon nitride film layer or a silicon oxide film layer is used as an anti-reflection film to achieve light transmittance and achieve an anti-reflection effect. Therefore, by setting an anti-reflection layer, the absorption rate of solar cells for light waves of 300nm to 1100nm can be significantly improved, and the reflectivity of light waves of 400nm to 700nm can be reduced to less than 1%. However, the above anti-reflection structures all have problems such as obvious blue edges, uneven surface color, and significant card mark marks, especially the problem that the battery appears blue under strong light, which makes the battery not beautiful enough. Summary of the invention

[0004] The present application provides a solar cell and a photovoltaic module to solve the technical problems of existing batteries such as obvious blue edges, uneven surface color, and obvious stuck point marks.

[0005] According to one aspect of the present application, a solar cell is provided, which includes a silicon wafer and an anti-reflection structure disposed on the surface of the silicon wafer, wherein the anti-reflection structure includes a first anti-reflection layer disposed on the surface of the silicon wafer and a second anti-reflection layer disposed on the surface of the first anti-reflection layer. The refractive index of the first anti-reflection layer is n1, the refractive index of the second anti-reflection layer is n2, and n1 and n2 satisfy one of the following relationships:

[0006] (a): -0.4≤n2-n1≤-0.05;

[0007] (b):0.1≤n2-n1≤0.4.

[0008] In an optional solution of the present application, 1.6≤n2≤2.6.

[0009] In an optional solution of the present application, the material of at least one of the first anti-reflection layer and the second anti-reflection layer is one, two or three of rare earth element compounds and transition metal compounds.

[0010] In an optional scheme of the present application, the rare earth elements in the rare earth element compound include one, two or three of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

[0011] In an optional scheme of the present application, the transition metal elements in the transition metal compound include one, two or three of Ti, V, Cu, Zn, Mo, W, Co, Ni and Re.

[0012] In an optional solution of the present application, the second anti-reflection layer includes an edge region and a middle region located inside the edge region, the thickness of the middle region is h1, and the thickness of the edge region is h2, wherein h1 and h2 satisfy the following relationship:

[0013] 0nm≤h1-h2≤40nm.

[0014] In an optional solution of the present application, the thickness of the first anti-reflection layer is H1, the thickness of the second anti-reflection layer is H2, and H1 and H2 satisfy the following functional relationship:

[0015] H1+H2=H+c

[0016] Wherein, H is the total thickness of the first anti-reflection layer and the second anti-reflection layer that enables the solar cell to present a specific color, and c is the thickness tolerance that enables the solar cell to present a specific color.

[0017] In an optional solution of the present application, 0<H2≤300.

[0018] In an optional scheme of the present application, the anti-reflection structure is constructed so that when the wavelength of the incident light is in the range of 300 to 1100 nm, its reflectivity shows a trend of decreasing, increasing, decreasing again, and increasing again as the wavelength increases, so as to form a reflectivity change curve characterized by double troughs.

[0019] In an optional solution of the present application, the second anti-reflection layer is cerium oxide, H=140 and -40<c<40, so that the solar cell appears black.

[0020] In an optional solution of the present application, the silicon wafer includes a main body and a suede structure formed on a surface of the main body, and the first anti-reflection layer is arranged on a surface of the suede structure.

[0021] According to another aspect of the present application, a photovoltaic module is provided. The photovoltaic module includes the above-mentioned solar cell.

[0022] In summary, the solar cell and photovoltaic module provided by the present application have at least the following beneficial effects:

[0023] In the present application, a double anti-reflection layer structure is designed based on the second anti-reflection layer and the first anti-reflection layer, and the difference in refractive index between the two is set within the above range, so that the double anti-reflection layer structure as a whole has a strong color adjustment effect, thereby ensuring that different parts of the battery still present the same color within a wider thickness range. Therefore, even if there is a certain difference in thickness between the edge and center of the battery, the present application is based on the above difference between the refractive index of the upper anti-reflection structure and the refractive index of the upper anti-reflection structure and the refractive index of the lower anti-reflection structure, so that the color of the edge and center of the battery is consistent within a wider thickness range, and the color of the card point area and other areas is consistent within a wider thickness range, so that the blue edge phenomenon and the card point mark can be weakened or even completely covered, thereby improving the color uniformity and aesthetics of the solar cell surface. In addition, since the solar cell of the present application has a wide tolerance range for thickness, under the condition of a suitable process range, the color ratio of high incident angle and low incident angle can be guaranteed to be consistent, so that the present application can also weaken the thickness change caused by different viewing angles and the resulting color difference problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation or the prior art description. Obviously, the drawings described below are some implementations of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic diagram of the structure of a solar cell provided according to one embodiment of the present application;

[0026] Figure 2 A schematic diagram of the structure of a second anti-reflection layer provided according to one embodiment of the present application;

[0027] Figure 3 The figure is a comparison diagram of the reflectivity of the anti-reflection structure of the solar cell 100 provided according to one embodiment of the present application and the reflectivity of the existing anti-reflection structure.

[0028] The reference numerals are as follows:

[0029] 100. Solar cells;

[0030] 10. Silicon wafer; 11. Main body; 12. Velvet structure;

[0031] 20. The first anti-reflection layer;

[0032] 30. Second anti-reflection layer; 31. Edge area; 32. Middle area. DETAILED DESCRIPTION

[0033] In the description of the present application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like appear to indicate the orientation or position relationship, unless otherwise specified, they are understood to be based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application.

[0034] In addition, if there is a feature defined as "first" or "second", it is only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Features defined as "first" or "second" may explicitly or implicitly include at least one of the defined features. If there is a description of "plurality", the general meaning is to include at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] In this application, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed" and so on should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection, it can be a direct connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0036] In the description of this specification, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it 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 application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0037] The photovoltaic module of the present application includes a stacked photovoltaic tempered glass, adhesive film, photovoltaic cell string and photovoltaic backplane or photovoltaic backplane glass structure for photovoltaic power generation. The photovoltaic cell string includes at least one solar cell 100 .

[0038] Specifically, the number of solar cells 100 in the photovoltaic cell string may be one or more. When the number of solar cells 100 in the photovoltaic cell string is more than one, the multiple solar cells 100 may be connected in series, in parallel, or in a combination of series and parallel to form a photovoltaic cell string.

[0039] The adhesive film is arranged between the photovoltaic tempered glass and the solar cell 100 of the photovoltaic cell string, and is usually an EVA adhesive film or a POE adhesive film. The refractive index of the adhesive film is generally in the range of 1.4 to 1.7. Therefore, changing the type of adhesive film or increasing the number of layers of the adhesive film usually does not affect the optical performance of the photovoltaic module.

[0040] Figure 1 The figure is a schematic diagram of the structure of a solar cell provided according to one embodiment of the present application.

[0041] See also Figure 1 The solar cell 100 of the present application includes a silicon wafer 10 and an anti-reflection structure arranged in sequence along its thickness direction. The anti-reflection structure includes a first anti-reflection layer 20 arranged on the surface of the silicon wafer 10 and a second anti-reflection layer 30 arranged on the surface of the first anti-reflection layer 20.

[0042] Specifically, the first anti-reflection layer 20 can be a film layer structure (also called an anti-reflection film) disposed on the surface of the silicon wafer 10 by PVD, CVD, etc., and the second anti-reflection layer 30 can also be a film layer structure (also called an anti-reflection film) disposed on the surface of the first anti-reflection layer 20 by PVD, CVD, etc.

[0043] In the solar cell 100 of the present application, the refractive index of the first anti-reflection layer 20 is n1, the refractive index of the second anti-reflection layer 30 is n2, and n1 and n2 satisfy the following relationship (a) or (b).

[0044] (a): -0.4≤n2-n1≤-0.05, that is, the refractive index of the second anti-reflection layer 30 located in the upper layer can be slightly lower than the refractive index of the first anti-reflection layer 20 located in the lower layer, and the second anti-reflection layer 30 and the first anti-reflection layer 20 are integrally formed into a refractive index gradient change structure. For example, n2-n1 can be -0.4, -0.35, -0.32, -0.3, -0.25, -0.23, -0.2, -0.15, -0.1, -0.05, etc.

[0045] (b): 0.1≤n2-n1≤0.4, that is, the refractive index of the second anti-reflection layer 30 located in the upper layer can be slightly higher than the refractive index of the first anti-reflection layer 20 located in the lower layer, and the second anti-reflection layer 30 and the first anti-reflection layer 20 are also formed as a refractive index gradient structure as a whole. For example, n2-n1 can be 0.1, 0.15, 0.18, 0.2, 0.23, 0.25, 0.3, 0.35, 0.38, 0.4, etc.

[0046] It should be noted that, since there is usually a certain difference in thickness between the edge and the center of the battery (e.g., a difference of 10nm), the existing anti-reflection structure has a higher blue light reflectivity at the edge of the battery than at the center under incident light (especially strong light), making the edge of the battery whiter than the center and the edge obviously blue. This phenomenon is called the blue edge phenomenon. In addition, the anti-reflection structure is usually formed on the silicon wafer of the battery by coating, and it is usually fixed by card points during the coating process. After coating, the film layer in the card point area is thinner and the color is different from other areas, thus forming an obvious mark, which leads to obvious card point marks on the battery.

[0047] In the present application, based on the design of the double anti-reflection layer structure of the second anti-reflection layer 30 and the first anti-reflection layer 20, the difference in refractive index between the two is set within the above range, so that the double anti-reflection layer structure as a whole has a strong color adjustment effect, thereby ensuring that different parts of the battery still present the same color within a wider thickness range. In other words, the color change of the solar cell 100 of the present application under incident light has a wider tolerance range for thickness.

[0048] Therefore, even when there is a certain difference in thickness between the edge and center of the battery, the present application, based on the upper anti-reflection structure and the above-mentioned difference between the refractive index of the upper anti-reflection structure and the refractive index of the lower anti-reflection structure, allows the edge and center of the battery to maintain consistent color within a wider thickness range, and the card point area and other areas to maintain consistent color within a wider thickness range, so that the blue edge phenomenon and the card point mark can be weakened or even completely concealed, thereby improving the color uniformity and aesthetics of the surface of the solar cell 100.

[0049] In addition, since the solar cell 100 of the present application has a wide tolerance range for thickness, under the condition of a suitable process range, the color ratio at high incident angles (side observation) and low incident angles (front observation) can be guaranteed to be consistent, so that the present application can also weaken the thickness changes caused by different viewing angles and the resulting color difference problems.

[0050] In some embodiments, 1.6≤n2≤2.6, for example, n2 can be 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2.0, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.5, 2.6, etc.

[0051] Among them, based on 1.6≤n2≤2.6, according to the relationship (a): -0.4≤n2-n1≤-0.05, we get 1.65≤n1≤2.8; according to the relationship (b): 0.1≤n2-n1≤0.4, we get 1.2≤n1≤2.5. In other words, 1.2≤n1≤2.8.

[0052] In this embodiment, based on the above relationship (a) or relationship (b) and the refractive index n2 of the second anti-reflection layer 30 within the above range, the refractive index n2 of the second anti-reflection layer 30 can be matched with the refractive index n1 of the first anti-reflection layer 20, and the refractive index n2 of the second anti-reflection layer 30 is made slightly higher or slightly lower than the refractive index n1 of the first anti-reflection layer 20, so that the second anti-reflection layer 30 and the first anti-reflection layer 20 as a whole form a refractive index gradient change structure, thereby significantly enhancing the overall color adjustment effect of the double-layer anti-reflection structure, thereby ensuring that the color change of the solar cell 100 of the present application under incident light is adapted to a wider thickness range.

[0053] For example, when the refractive index n1 of the first anti-reflection layer 20 is selected to be 2.0, the refractive index n2 of the second anti-reflection layer 30 may be 1.6 to 1.95 or 2.1 to 2.4. Preferably, n2 may be 1.7 to 1.8 or 2.2 to 2.3.

[0054] In some embodiments, in order to ensure that the refractive index n1 of the first anti-reflection layer 20 and the refractive index n2 of the second anti-reflection layer 30 can satisfy the relationship (a) or (b), the material of at least one of the first anti-reflection layer 20 and the second anti-reflection layer 30 may be one, two or three of rare earth element compounds and transition metal compounds.

[0055] Rare earth element compounds are compounds composed of rare earth elements and other non-rare earth elements, and transition metal compounds are compounds composed of transition metal elements and other non-transition metal elements. Further, the rare earth elements in the rare earth element compounds include one, two or three of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and the transition metal elements in the transition metal compounds include one, two or three of Ti, V, Cu, Zn, Mo, W, Co, Ni, and Re.

[0056] In this embodiment, since the first anti-reflection layer 20 and / or the second anti-reflection layer 30 are made of rare earth element compounds and transition metal compounds, the refractive index of the first anti-reflection layer 20 and / or the second anti-reflection layer 30 can reach between 1.6 and 2.6, the second anti-reflection layer 30 and the first anti-reflection layer 20 can form a special refractive index gradient change structure, which can significantly increase the light absorption capacity of the solar cell 100. In addition, the special refractive index of this type of material can realize a double anti-reflection layer structure with a refractive index difference of 0.1 to 0.4, thereby realizing a reflectivity change curve with double trough characteristics. By specifically selecting the rare earth element or transition metal element in the second anti-reflection layer 30 and controlling the thickness of the second anti-reflection layer 30, the purpose of reducing blue light reflection, increasing near-infrared light absorption, or increasing red light and green light reflection can be achieved, thereby suppressing the efficiency attenuation of the solar cell 100 and adjusting the battery color at the same time.

[0057] Exemplarily, the second anti-reflection layer 30 may be cerium oxide (CeO2), yttrium oxide, tungsten oxide, etc., so that the refractive index n2 of the second anti-reflection layer 30 can reach between 1.6 and 2.6. In addition, cerium oxide, yttrium oxide, and tungsten oxide are resistant to high temperatures, and their optical properties are not affected by high temperatures, and they will not change during the process and in the use scenario. They have the function of absorbing ultraviolet rays, which can reduce the UV attenuation of the solar cell 100, improve the ultraviolet tolerance of the cell, and have better applicability to areas with strong ultraviolet radiation (deep space, plateaus, high latitudes, deserts).

[0058] In some embodiments, the material of the first anti-reflection layer 20 may be one, two or three of silicon nitride, rare earth element compounds and transition metal compounds.

[0059] Exemplarily, the material of the first anti-reflection layer 20 is silicon nitride, and the second anti-reflection layer 30 is a rare earth element compound (such as CeO2); or, the material of the first anti-reflection layer 20 is silicon nitride, and the second anti-reflection layer 30 is a transition metal compound; or, the material of the first anti-reflection layer 20 is a rare earth element compound (such as CeO2), and the second anti-reflection layer 30 may be a transition metal compound; or, the material of the first anti-reflection layer 20 is a rare earth element compound (such as CeO2), and the second anti-reflection layer 30 is a rare earth element compound (such as CeO2); or Alternatively, the material of the first anti-reflection layer 20 is a transition metal compound, and the second anti-reflection layer 30 is a rare earth element compound (such as CeO2); or, the material of the first anti-reflection layer 20 is a transition metal compound, and the second anti-reflection layer 30 is a transition metal compound, etc.; or, the material of the first anti-reflection layer 20 is a rare earth element compound (such as CeO2), and the second anti-reflection layer 30 is silicon nitride; or, the material of the first anti-reflection layer 20 is a rare earth element compound (such as CeO2), and the second anti-reflection layer 30 is a rare earth element compound (such as Nd2O3)

[0060] Therefore, based on the double anti-reflection layer structure design of the second anti-reflection layer 30 and the first anti-reflection layer 20, the second anti-reflection layer 30 and the first anti-reflection layer 20 in the present application have more material options, and through the specific material selection of the first anti-reflection layer 20 and the second anti-reflection layer 30 and the thickness adjustment of the first anti-reflection layer 20 and the second anti-reflection layer 30, the peak position and peak value of the reflectivity change curve of the double anti-reflection layer structure can be controlled to achieve the adjustment of battery efficiency and color.

[0061] Continue reading Figure 1The silicon wafer 10 includes a main body 11 and a velvet structure 12 formed on the surface of the main body 11, and a first anti-reflection layer 20 is disposed on the surface of the velvet structure 12. The velvet structure 12 may be a pyramid-shaped surface structure, and the first anti-reflection layer 20 covers each surface portion of the velvet structure 12. The velvet structure 12 changes the surface structure of the silicon wafer 10, and achieves an anti-reflection effect by changing the optical path of the incident light.

[0062] Figure 2 It is a schematic structural diagram of a second anti-reflection layer provided according to one embodiment of the present application.

[0063] See also Figure 2 The second anti-reflection layer 30 includes an edge region 31 and a middle region 32 located inside the edge region 31. The thickness of the middle region 32 is h1, the thickness of the edge region 31 is h2, and h1 and h2 satisfy the following relationship:

[0064] 0nm≤h1-h2≤40nm.

[0065] Exemplarily, the value of h1-h2 may be 0 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, etc.

[0066] When the second anti-reflection layer 30 is formed by coating the surface of the first anti-reflection layer 20 by PVD, CVD or the like, there will be a thickness difference between the edge region 31 and the middle region 32 of the second anti-reflection layer 30 due to the limitation or influence of the process conditions. Since the second anti-reflection layer 30 of the present application is a new film layer structure formed on the basis of the first anti-reflection layer 20, based on the double anti-reflection layer structure design composed of the second anti-reflection layer 30 and the first anti-reflection layer 20, when the thickness difference between the edge region 31 and the middle region 32 of the second anti-reflection layer 30 is within the above-mentioned wide range, the colors of the edge region 31 and the middle region 32 can be basically consistent under the irradiation of incident light, so that the blue edge phenomenon can be weakened or even completely covered, thereby improving the color uniformity and aesthetics of the surface of the solar cell 100. Compared with the existing anti-reflection structure, the thickness difference between the edge region 31 and the middle region 32 of the second anti-reflection layer 30 has a wider selection range. For example, when the thickness difference between the edge area and the middle area of ​​the film layer of the existing anti-reflection structure is less than 10nm, the thickness difference between the edge area 31 and the middle area 32 of the second anti-reflection layer 30 of the present application can be less than 40nm. At this time, the solar cell 100 of the present application at least has or even exceeds the color uniformity effect of the existing cells.

[0067] In the present application, by matching the refractive index of the first anti-reflection layer 20 with the second anti-reflection layer 30, the blue light reflectivity of the edge area 31 of the second anti-reflection layer 30 can be reduced by 2% compared with the edge area of ​​the existing single anti-reflection layer structure, and the proportion of this difference in the reflected light is diluted under the double anti-reflection layer structure design, so that the impact is relatively small, so that the surface color of the solar cell 100 is uniform and presents a specific color.

[0068] In addition, the PVD and CVD tooling can be improved to achieve full-surface coating using grooves without card points, so that the front side is not blocked. Therefore, after coating, the entire surface is covered by the second anti-reflection layer 30, and the surface of the solar cell 100 has no card point prints or blue edges and is in a single color.

[0069] In some embodiments, the thickness of the first anti-reflection layer 20 is H1, the thickness of the second anti-reflection layer 30 is H2, and H1 and H2 satisfy the following functional relationship:

[0070] H1+H2=H+c.

[0071] Wherein, H is the total thickness of the first anti-reflection layer 20 and the second anti-reflection layer 30 that make the solar cell 100 present a specific color, and c is a constant and is the thickness tolerance (also called thickness variation range) that makes the solar cell 100 present a specific color. For example, when H=140 and c is -40nm to 40nm, the solar cell 100 appears black.

[0072] It should be noted that H is the median value (also called the mean value) of the total thickness of the first anti-reflection layer 20 and the second anti-reflection layer 30, and different H values ​​correspond to solar cells 100 of different colors. H1 is the thickness value corresponding to a certain part of the first anti-reflection layer 20, H2 is the thickness value corresponding to a certain part of the second anti-reflection layer 30, and H1 and H2 are the same area of ​​the battery. Different ranges of c values ​​also correspond to solar cells 100 of different colors. Exemplarily, when c is -40nm to 40nm and H=140, the solar cell 100 appears black.

[0073] The above functional relationship between H1+H2 and H is a derivative relationship based on the refractive index difference between the two anti-reflection layers and Fresnel's law. The color change of the solar cell 100 has the characteristic of periodic change with thickness change. Based on the newly added second anti-reflection layer 30, the color change period, total thickness median and thickness range of the solar cell 100 change with the refractive index difference between the two anti-reflection layers.

[0074] Based on the above functional relationship between H1+H2 and H, the thicknesses of the first anti-reflection layer 20 and the second anti-reflection layer 30 can be quickly adjusted so that the solar cell 100 can present a specific color.

[0075] In some embodiments, 0<H2≤300, for example, H2 may be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 100nm, 150nm, 200nm, 250nm, 300nm, etc. Preferably, 50≤H2≤80.

[0076] In some examples, for a solar cell 100 of a specific color, when the materials of the second anti-reflection layer 30 and the first anti-reflection layer 20 change, the H value of the solar cell 100 of the specific color will also change accordingly. For example, H can be 20nm, 50nm, 70nm, 95nm, or 150nm.

[0077] Based on the double anti-reflection layer structure design consisting of the second anti-reflection layer 30 and the first anti-reflection layer 20, when the second anti-reflection layer 30 is under this thickness condition, the colors of the edge area 31 and the middle area 32 of the second anti-reflection layer 30 can be basically consistent, so the color uniformity of the solar cell 100 after coating is good.

[0078] Figure 3 This is a comparison diagram of the reflectivity of the anti-reflection structure of the solar cell 100 provided according to one of the embodiments of the present application and the reflectivity of the existing anti-reflection structure, wherein the red curve in the figure represents the reflectivity change curve of the anti-reflection structure of the solar cell 100 of the present application, and the blue curve represents the reflectivity change curve of the existing anti-reflection structure.

[0079] See also Figure 3 The first anti-reflection layer 20 and the second anti-reflection layer 30 form a double anti-reflection layer structure. When the wavelength of the incident light is in the spectral range of 300 to 1100 nm, the reflectivity of the double anti-reflection layer structure shows a trend of decreasing, increasing, decreasing again, and increasing again as the wavelength increases, so as to form a reflectivity change curve characterized by double troughs, that is, the reflectivity change curve of the double anti-reflection layer structure has two trough points with low reflectivity and a light wavelength region with higher reflectivity.

[0080] For a battery with a single anti-reflection layer structure, when the wavelength of incident light is within the spectral range of 300 to 1100 nm, its reflectivity shows a trend of decreasing, increasing, and then increasing again as the wavelength increases, forming a reflectivity change curve characterized by a single trough.

[0081] Although the battery with a single anti-reflection layer structure can achieve a specific target color on the front side by adjusting the color spectrum distribution, the difference in thickness between the edge and the middle will still lead to a serious blue edge problem, and the loss of visible light or near-infrared light is high, resulting in a large loss of efficiency. The double anti-reflection layer structure composed of the second anti-reflection layer 30 and the first anti-reflection layer 20 of the present application can achieve the selection of specific colors, the same color of the edge and the middle, and the 700-1000nm near-infrared light absorption gain (the characteristic of this gain range is that the wavelength range of the transmittance enhancement is slightly lower than the wavelength corresponding to the solar cell energy band) through the characteristics of double troughs and adjusting the color spectrum, so as to suppress the efficiency attenuation of the solar cell 100 while adjusting the color.

[0082] See also Figure 3 In a specific embodiment, the first anti-reflection layer 20 of the solar cell 100 of the present application is silicon nitride, and the second anti-reflection layer 30 is CeO2. The existing cells with a single anti-reflection layer structure use silicon nitride as the anti-reflection layer. Compared with the single silicon nitride anti-reflection layer structure, the present application forms a double anti-reflection layer structure by adding a CeO2 anti-reflection layer. The reflectivity of the double anti-reflection layer structure can achieve a double trough (near 480nm and near 930nm). Among them, the reflectivity of 480nm is 0.75%, the reflectivity of 600nm is 1.29%, and the reflectivity of 930nm is 0.37%. The reflectivity of 480nm and 930nm is lower than that of 600nm. When there is only a single silicon nitride anti-reflection layer, its reflectivity presents a single trough (near 460nm).

[0083] Further reading Figure 3 The wavelength band selectively increased between the double troughs is the wavelength required to achieve a specific target color for the solar cell 100. When black is the target color, by adjusting the thickness of CeO2, the reflectivity of red and green light in the range of 450-750nm can be increased by about 2%, and the characteristic of the solar cell 100 being black can be achieved, that is, the reflectivity of a specific color can be selectively increased, so that the difference between the reflectivity curve of the solar cell 100 and the reflectivity curve of the black material in the visible light range is less than 1.5%, thereby achieving the target color. Secondly, the 700-1000nm near-infrared light region is more than 1% lower than the minimum value of the cell reflectivity of a single anti-reflection layer, which is a characteristic of the double trough to achieve near-infrared light absorption gain.

[0084] Therefore, the transmittance or reflectance of a specific wavelength (specific color) can be selectively increased by adjusting the thickness of the second anti-reflection layer 30. Secondly, the cell surface colors formed by the first anti-reflection layer 20 with different thicknesses are different. Therefore, by matching the first anti-reflection layer 20 with a specific thickness with the second anti-reflection layer 30 with a specific thickness, the ratio of the three primary colors of red, green and blue can be adjusted, and a solar cell 100 with a specific color can be formed.

[0085] The influence of the color of the solar cell 100 is described below by combining the material and thickness selection of the first anti-reflection layer 20 and the second anti-reflection layer 30 with examples.

[0086] Table 1 Relationship between silicon nitride thickness and battery color

[0087] Silicon nitride thickness Battery 1 Color 40-60nm Yellow or red 60-70nm blue 70-100nm Light blue 120-160nm yellow 180-200nm red 200-230nm blue

[0088] Table 2 Effect of CeO2 thickness on battery color

[0089]

[0090] Table 3 Matching relationship between silicon nitride film thickness and CeO2 film thickness of black battery

[0091]

[0092]

[0093] Among them, the color of battery 1 in Table 1-3 refers to the color of the front of the battery with a silicon nitride film layer and no CeO2, POE, glass and other materials. The color of battery 2 refers to the color of the front of the battery with a silicon nitride film layer and a CeO2 film layer. The component color refers to the color of the front of the battery with silicon nitride, CeO2, POE, and glass. When the battery structure and film material are different, there is a certain deviation in the above relationship between thickness and color, and there is a color transition in the thickness change process. The color of battery 3 above takes black as an example, but it is not limited to black, and can also be yellow, red and other target colors.

[0094] The present application can selectively increase the reflectivity or transmittance of certain visible light by matching the thickness and material of the second anti-reflection layer 30 with the first anti-reflection layer 20, and can balance the ratio of the three primary colors of red, green and blue, so that the reflectivity difference of the solar cell 100 to visible light does not exceed 1.5%, thereby forming a black solar cell 100. This method can also increase the reflectivity of a specific color, thereby forming a solar cell 100 of a specific color.

[0095] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Those skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A solar cell (100), characterized in that: It comprises a silicon wafer (10) and an anti-reflection structure arranged on the surface of the silicon wafer (10), wherein the anti-reflection structure comprises a first anti-reflection layer (20) arranged on the surface of the silicon wafer (10) and a second anti-reflection layer (30) arranged on the surface of the first anti-reflection layer (20); The refractive index of the first anti-reflection layer (20) is n1, the refractive index of the second anti-reflection layer (30) is n2, and n1 and n2 satisfy one of the following relationships: (a): -0.4≤n2-n1≤-0.05; (b):0.1≤n2-n1≤0.

4.

2. The solar cell (100) according to claim 1, characterized in that 1.6≤n2≤2.6。 3. The solar cell (100) according to claim 1, characterized in that The material of at least one of the first anti-reflection layer (20) and the second anti-reflection layer (30) is one, two or three of a rare earth element compound and a transition metal compound.

4. The solar cell (100) according to claim 3, characterized in that: The rare earth elements in the rare earth element compound include one, two or three of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; and / or The transition metal elements in the transition metal compound include one, two or three of Ti, V, Cu, Zn, Mo, W, Co, Ni and Re.

5. The solar cell (100) according to claim 1, characterized in that: The second anti-reflection layer (30) comprises an edge region (31) and a middle region (32) located inside the edge region (31), the thickness of the middle region (32) is h1, and the thickness of the edge region (31) is h2, wherein h1 and h2 satisfy the following relationship: 0nm≤h1-h2≤40nm.

6. The solar cell (100) according to any one of claims 1 to 5, characterized in that: The thickness of the first anti-reflection layer (20) is H1, and the thickness of the second anti-reflection layer (30) is H2. H1 and H2 satisfy the following functional relationship: H1+H2=H+c Wherein, H is the total thickness of the first anti-reflection layer (20) and the second anti-reflection layer (30) that enables the solar cell (100) to present a specific color, and c is the thickness tolerance that enables the solar cell (100) to present a specific color.

7. The solar cell (100) according to claim 6, characterized in that: 0≤H2≤300。 8. The solar cell (100) according to claim 6, characterized in that: The anti-reflection structure is constructed so that when the wavelength of the incident light is within the range of 300 to 1100 nm, its reflectivity shows a trend of decreasing, increasing, decreasing again, and increasing again as the wavelength increases, so as to form a reflectivity change curve characterized by double troughs.

9. The solar cell (100) according to claim 8, characterized in that: The second anti-reflection layer (30) is cerium oxide, H=140 and -40<c<40, so that the solar cell (100) appears black.

10. The solar cell (100) according to claim 1, characterized in that: The silicon wafer (10) comprises a main body (11) and a velvet structure (12) formed on the surface of the main body (11); the first anti-reflection layer (20) is arranged on the surface of the velvet structure (12).

11. A photovoltaic module, characterized in that: Comprising at least one solar cell (100) according to any one of claims 1 to 10.

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