Photovoltaic encapsulation structure, photovoltaic cell and photovoltaic module

Abstract

The application relates to a photovoltaic packaging structure, a photovoltaic cell and a photovoltaic assembly. The photovoltaic packaging structure comprises a packaging layer, a single-line state splitting layer, a radiation recombination layer and an optical series connection layer. The single-line state splitting layer is arranged on one side of the packaging layer. The radiation recombination layer is arranged on the side of the single-line state splitting layer away from the packaging layer. The radiation recombination layer is used for receiving and recombining the electron-hole pairs generated by the single-line state splitting layer to generate photons. The optical series connection layer is arranged on the side of the radiation recombination layer away from the single-line state splitting layer. The optical series connection layer is used for electrically insulating the radiation recombination layer from the solar cell, and the photons generated by the radiation recombination layer are transmitted and incident on the solar cell. The single-line state splitting layer can be arranged away from the light-receiving surface of the solar cell, the optical series connection between the single-line state splitting layer and the solar cell is ensured, and the conversion efficiency of the solar cell is effectively improved by using the single-line state splitting layer.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to photovoltaic packaging structures, photovoltaic cells, and photovoltaic modules. Background Technology

[0002] With the development of solar cell technology, the conversion efficiency of crystalline silicon solar cells has approached the theoretical upper limit of 29.4%. Perovskite cells, however, suffer from poor stability and cannot meet the lifespan requirements of photovoltaic modules under long-term outdoor conditions. Single-line splitting technology has become another important and effective technological direction for improving the conversion efficiency of solar cells.

[0003] Singlet Fission (SF) materials, unlike traditional photovoltaic materials where absorbing a photon with energy greater than its band gap can only excite one electron-hole pair, can generate two electron-hole pairs from the absorption of a photon with energy greater than its band gap. When SF materials are applied to solar cells, the high-energy photons can generate twice as many electron-hole pairs as the solar cell itself, thereby improving the current and energy conversion efficiency of the solar cell.

[0004] However, directly placing SF materials on the light-receiving surface of a solar cell cannot achieve efficient radiative recombination of photogenerated carriers to provide additional incident photons, thus limiting the improvement of the conversion efficiency of solar cells by SF materials. Summary of the Invention

[0005] Therefore, it is necessary to provide a photovoltaic encapsulation structure, photovoltaic cell, and photovoltaic module to address the problem that directly placing SF material on the light-receiving surface of the solar cell limits the improvement of the conversion efficiency of the solar cell.

[0006] In a first aspect, embodiments of this application provide a photovoltaic encapsulation structure, including:

[0007] Encapsulation layer;

[0008] A single-line split layer is provided on one side of the encapsulation layer;

[0009] A radiative recombination layer is disposed on the side of the singlet split layer opposite to the encapsulation layer; the radiative recombination layer is used to receive and recombine the electron-hole pairs generated by the singlet split layer to generate photons.

[0010] An optical tandem layer is disposed on the side of the radiative recombination layer opposite to the singlet split layer. The optical tandem layer is used to electrically insulate the radiative recombination layer from the solar cell and to allow photons generated by the radiative recombination layer to be transmitted and incident on the solar cell.

[0011] In some embodiments, the internal quantum efficiency of the radiation composite layer is greater than or equal to 95%.

[0012] In some embodiments, the lowest empty orbital energy level of the radiative recombination layer is less than or equal to the energy level of the triplet multiplication electron generated by the singlet splitting.

[0013] In some embodiments, the thickness of the radiation composite layer is greater than or equal to 100 nm and less than or equal to 300 nm.

[0014] In some embodiments, the material of the radiation composite layer includes lead selenide quantum dots.

[0015] In some embodiments, the resistivity of the optical tandem layer is greater than or equal to 10. 8 Ω·cm; the transmittance of the optical tandem layer is greater than or equal to 95%.

[0016] In some embodiments, the refractive index of the optical tandem layer is greater than the refractive index of the radiation composite layer.

[0017] In some embodiments, the thickness of the optical tandem layer is greater than or equal to 200 nm and less than or equal to 6000 nm.

[0018] In some embodiments, the optical tandem layer is made of nitrogen-doped hafnium oxide.

[0019] In some embodiments, the thickness of the singlet crack layer is greater than or equal to 200 nm and less than or equal to 1000 nm.

[0020] In some embodiments, the material of the singlet split layer includes one of tetraphenyl, triphenyl, and dipyrrolonaphthidine dione.

[0021] In some embodiments, the refractive index of the encapsulation layer is less than or equal to the refractive index of the optical tandem layer.

[0022] In some embodiments, the thickness of the encapsulation layer is greater than or equal to 1 μm and less than or equal to 1 mm.

[0023] In some embodiments, the encapsulation layer is made of at least one of ethylene-vinyl acetate copolymer, polyolefin elastomer, thermoplastic polyolefin, UV-curable adhesive, and silicone polymer.

[0024] Secondly, embodiments of this application provide a photovoltaic cell, including a solar cell and a photovoltaic encapsulation structure as described in any embodiment of the first aspect, wherein the photovoltaic encapsulation structure is disposed on the light-receiving surface of the solar cell, and the optical series layer is located between the radiation recombination layer and the light-receiving surface of the solar cell.

[0025] Thirdly, embodiments of this application provide a photovoltaic module, including a solar cell and a photovoltaic encapsulation structure according to any embodiment of the first aspect, wherein the photovoltaic encapsulation structure is disposed on the light-receiving surface of the solar cell, and the optical series layer is located between the radiation composite layer and the light-receiving surface of the solar cell.

[0026] The aforementioned photovoltaic encapsulation structure, by sequentially stacking an encapsulation layer, a singlet splitting layer, a radiative recombination layer, and an optical tandem layer, constitutes a photovoltaic encapsulation structure for solar cells. The optical tandem layer is located between the radiative recombination layer and the light-receiving surface of the solar cell. The singlet splitting layer utilizes the singlet splitting effect to absorb high-energy photons and generate multiplied electron-hole pairs. The radiative recombination layer receives and causes the electron-hole pairs generated by the singlet splitting layer to recombine and generate photons. The optical tandem layer electrically insulates the radiative recombination layer and the solar cell, and allows the photons generated by the radiative recombination layer to be transmitted and incident on the solar cell. In this way, the optical tandem between the singlet splitting layer and the solar cell can be ensured, enabling the multiplied electron-hole pairs in the singlet splitting layer to radiate and recombine efficiently, generating additional multiplied incident light for the solar cell to absorb. This causes the solar cell to absorb photons and generate additional electron-hole pairs, achieving a carrier multiplication effect, thereby effectively improving the conversion efficiency of the solar cell. In addition, by integrating the singlet split layer into the photovoltaic encapsulation structure, instead of placing the singlet split layer directly on the light-receiving surface of the solar cell, there is no need to consider complex constraints such as solar cell surface passivation and interface energy level matching, which greatly reduces the difficulty of structural adaptation and process integration, and at the same time, there is no need to change the structure and fabrication process of the solar cell. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the photovoltaic encapsulation structure in some embodiments of this application.

[0028] Figure 2 This is a schematic diagram of the structure of a photovoltaic cell or photovoltaic module in some embodiments of this application.

[0029] Figure 3 This is a schematic diagram of the structure of a photovoltaic cell or photovoltaic module in some other embodiments of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 10. Photovoltaic encapsulation structure; 11. Encapsulation layer; 12. Single-line splitting layer; 13. Radiative composite layer; 14. Optical tandem layer;

[0032] 20. Solar cells. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0035] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0039] As described in the background section, singlet Fission (SF) materials, unlike traditional photovoltaic materials where absorbing a photon with energy greater than its band gap can only excite one electron-hole pair, can generate two electron-hole pairs from the absorption of a photon with energy greater than its band gap. When SF materials are applied to solar cells, the high-energy photons can generate twice as many electron-hole pairs as the solar cell itself, thereby improving the current and energy conversion efficiency of the solar cell.

[0040] However, directly placing SF materials on the light-receiving surface of a solar cell cannot achieve efficient radiative recombination of photogenerated carriers to provide additional incident photons, thus limiting the improvement of the conversion efficiency of solar cells by SF materials.

[0041] To address the aforementioned technical issues, a photovoltaic encapsulation structure, a photovoltaic cell, and a photovoltaic module are provided, which can avoid the direct placement of single-line split layers on the light-receiving surface of the solar cell, ensure optical series connection between the single-line split layers and the solar cell, and effectively utilize the single-line split layers to improve the conversion efficiency of the solar cell.

[0042] The optical elements provided in the embodiments of this application are described below with reference to the accompanying drawings and some embodiments, but are not limited thereto.

[0043] See Figure 1As shown, in a first aspect, embodiments of this application provide a photovoltaic encapsulation structure 10, including an encapsulation layer 11, a singlet split layer 12, a radiative recombination layer 13, and an optical tandem layer 14. The singlet split layer 12 is disposed on one side of the encapsulation layer 11; the radiative recombination layer 13 is disposed on the side of the singlet split layer 12 away from the encapsulation layer 11; the radiative recombination layer 13 is used to receive and recombine electron-hole pairs generated by the singlet split layer 12 to generate photons; the optical tandem layer 14 is disposed on the side of the radiative recombination layer 13 away from the singlet split layer 12, and the optical tandem layer 14 is used to electrically insulate the radiative recombination layer 13 from the solar cell 20, and to allow the photons generated by the radiative recombination layer 13 to be transmitted and incident on the solar cell 20.

[0044] In some examples, the singlet split layer 12 can absorb high-energy photons, producing a high-energy singlet exciton (energy level E). s1 Then, the high-energy singlet exciton undergoes a singlet splitting process to produce two low-energy triplet excitons (energy level E). T1 This enables the carrier multiplication process. Based on the above principle, the singlet split layer 12 needs to meet the following requirements:

[0045] The singlet exciton energy E of singlet split layer 12 s1 Greater than or equal to the triplet exciton energy E T1 Twice as much.

[0046] The triplet exciton energy E of singlet split layer 12 T1 The semiconductor bandgap E of the solar cell 20 is greater than or equal to that of the solar cell 20. g-pv In this way, the photons released after the triplet exciton undergoes radiative recombination can excite the solar cell 20 and be effectively absorbed by the solar cell 20, thereby achieving a multiplication of charge carriers.

[0047] In some examples, if solar cell 20 is a crystalline silicon cell, E T1 ≥1.12eV; If the solar cell 20 is a thin-film cell, the triplet exciton energy ET1 must be greater than or equal to the semiconductor bandgap of the absorber layer of the thin-film cell. For example, when the thin-film cell is a perovskite cell, the triplet exciton energy E T1 The semiconductor bandgap is greater than or equal to that of the perovskite layer.

[0048] If the singlet split layer 12 is directly disposed on the light-receiving surface of the solar cell 20, the singlet split layer 12 is directly electrically connected in series with the solar cell 20. Since the surface of the solar cell 20 has a large number of defects, these defects can trap the holes or electrons generated by the singlet split layer 12, making it impossible to form a current, let alone achieve the high-efficiency radiative recombination of the multiplied photogenerated carriers (electron-hole pairs) in the singlet split layer 12, and generate additional multiplied photons for the solar cell 20 to absorb. In this application, the radiative recombination layer 13 is used to receive and cause the electron-hole pairs generated by the singlet split layer 12 to recombine and generate photons. The optical tandem layer 14 is disposed on the side of the radiative recombination layer 13 away from the singlet split layer 12. The optical tandem layer 14 is used to electrically insulate the radiative recombination layer 13 from the solar cell 20, and to allow the photons generated by the radiative recombination layer 13 to be transmitted and incident on the solar cell 20. That is to say, the optical tandem layer 14 plays the role of optical tandem and electrical insulation, so that the electron-hole pairs reaching the radiative recombination layer 13 cannot directly reach the surface of the solar cell 20, but recombine and generate photons within the radiative recombination layer 13. The generated photons are incident on the solar cell 20 through the optical tandem layer 14, thereby ensuring the optical tandem between the singlet split layer 12 and the solar cell 20. After the solar cell 20 absorbs the multiplied photons, it excites and generates additional electron-hole pairs, thereby achieving the effect of carrier multiplication and effectively improving the conversion efficiency of the solar cell 20.

[0049] In addition, by integrating the encapsulation layer 11, the single-line split layer 12, the radiation composite layer 13, and the optical tandem layer 14 to form a photovoltaic encapsulation structure 10, the single-line split layer 12 can be avoided from being directly placed on the light-receiving surface of the solar cell 20. In this way, there is no need to consider complex constraints such as surface passivation and interface energy level matching of the solar cell 20, which greatly reduces the difficulty of structural adaptation and process integration, and at the same time, there is no need to change the structure and fabrication process of the solar cell 20.

[0050] In summary, the photovoltaic encapsulation structure 10 provided in this application embodiment is formed by sequentially stacking an encapsulation layer 11, a singlet splitting layer 12, a radiative recombination layer 13, and an optical tandem layer 14 to constitute a photovoltaic encapsulation structure 10 for a solar cell 20. The optical tandem layer 14 is disposed between the radiative recombination layer 13 and the light-receiving surface of the solar cell 20. The singlet splitting layer 12 absorbs high-energy photons and generates multiplied electron-hole pairs using the singlet splitting effect. The radiative recombination layer 13 receives and recombines the electron-hole pairs generated by the singlet splitting layer 12 to generate photons. The optical tandem layer 14... 4. Electrical insulation is provided between the radiative recombination layer 13 and the solar cell 20, allowing photons generated by the radiative recombination layer 13 to be transmitted and incident on the solar cell 20. This ensures optical series connection between the singlet split layer 12 and the solar cell 20, enabling highly efficient radiative recombination of electrons and holes multiplied in the singlet split layer 12. This generates additional incident light that is absorbed by the solar cell 20, causing the solar cell 20 to generate additional electron-hole pairs after absorbing photons, achieving a carrier multiplication effect and effectively improving the conversion efficiency of the solar cell 20. Furthermore, by integrating the singlet split layer 12 into the photovoltaic encapsulation structure 10, rather than directly placing it on the light-receiving surface of the solar cell 20, complex constraints such as surface passivation and interface energy level matching of the solar cell 20 are eliminated, significantly reducing the difficulty of structural adaptation and process integration, while also requiring no changes to the structure and fabrication process of the solar cell 20.

[0051] In some embodiments, the internal quantum efficiency (IQE) of the radiative composite layer 13 is greater than or equal to 95%.

[0052] Therefore, by making the internal quantum efficiency of the radiative recombination layer 13 greater than or equal to 95%, it can be ensured that the radiative recombination ratio of the multiplied carriers generated by the singlet split layer 12 is extremely high, minimizing the non-radiative loss of carriers, ensuring that enough recombination photons are output for absorption and utilization by the solar cell 20, and stably realizing the multiplication of carriers and the improvement of conversion efficiency.

[0053] In some embodiments, the lowest empty orbital energy level of the radiative complex layer 13 is less than or equal to the energy level of the triplet multiplication electron generated by the singlet split layer 12.

[0054] Since the charge carriers generated in the singlet split layer 12 need to be effectively injected into the radiative recombination layer 13, the interface barrier between the radiative recombination layer 13 and the singlet split layer 12 cannot be too large. In this embodiment, by making the lowest empty orbital energy level of the radiative recombination layer 13 less than or equal to the energy level of the triplet-multiplying electrons generated in the singlet split layer 12, the charge carriers generated in the singlet split layer 12 can be smoothly injected into the radiative recombination layer 13, significantly increasing the radiative recombination probability of electron-hole pairs, promoting the efficient generation of photons that can be transmitted and absorbed by the solar cell 20, realizing the directional transport and efficient recombination of charge carriers, reducing energy loss during the charge carrier injection process, fully utilizing the charge carrier multiplication advantage of singlet splitting, and ensuring an effective improvement in the conversion efficiency of the solar cell 20.

[0055] In some of these embodiments, see Figure 1 As shown, the thickness of the radiation composite layer 13 is greater than or equal to 100 nm and less than or equal to 300 nm.

[0056] Therefore, by making the thickness of the radiative recombination layer 13 greater than or equal to 100 nm and less than or equal to 300 nm, sufficient interaction space and recombination region can be provided for the multiplied carriers generated by the singlet split layer 12, ensuring that electron-hole pairs can radiatively recombine within the radiative recombination layer 13. This avoids insufficient carrier recombination paths and incomplete recombination due to the radiative recombination layer 13 being too thin, resulting in a large number of multiplied carriers failing to effectively annihilate and emit light, thus causing energy loss. At the same time, it can also avoid the problem of increased internal defects caused by excessive thickness of the radiative recombination layer 13, effectively suppressing defect-induced non-radiative recombination pathways, reducing the proportion of carriers dissipated in the form of heat energy, maintaining a high internal quantum efficiency of the radiative recombination layer 13, ensuring that the vast majority of multiplied carriers can generate photons in the form of radiative recombination, stably providing absorbable and usable incident photons for the solar cell 20, effectively leveraging the advantages of singlet split carrier multiplication, and ensuring an effective improvement in the conversion efficiency of the solar cell 20.

[0057] In some embodiments, the material of the radiation composite layer 13 includes lead selenide quantum dots.

[0058] Therefore, by using lead selenide quantum dots for the radiative recombination layer 13, and taking advantage of the inherent characteristics of lead selenide quantum dots—tunable bandgap, excellent exciton level matching, and wide light absorption and emission spectral range—it can achieve good energy level matching with the triplet-state multiplying carriers generated by the singlet splitting layer 12. This allows for the efficient acceptance and confinement of triplet-state multiplying electrons and holes, promoting rapid encounters and radiative recombination of carriers within the layer, significantly improving radiative recombination efficiency and internal quantum efficiency. Simultaneously, the emission wavelength of lead selenide quantum dots can precisely match the spectral response range of the solar cell 20, enabling the photons generated by radiative recombination to be efficiently absorbed and utilized by the solar cell 20, reducing photon energy waste and spectral mismatch losses. Furthermore, lead selenide quantum dots possess advantages such as fast carrier relaxation rate and low non-radiative recombination defect density, effectively suppressing carrier dissipation as heat energy and maximizing the proportion of multiplied carriers converted into photons. This further leverages the carrier multiplication effect of singlet splitting, ensuring an effective improvement in the conversion efficiency of the solar cell 20.

[0059] In some of these embodiments, see Figure 1 As shown, the resistivity of the optical tandem layer 14 is greater than or equal to 108 Ω·cm; the transmittance of the optical tandem layer 14 is greater than or equal to 95%.

[0060] Therefore, by limiting the resistivity of the optical series layer 14 to no less than 108 Ω·cm, the optical series layer 14 can have excellent insulation properties, effectively isolating the electrical conduction between the radiation recombination layer 13 and the solar cell 20, and ensuring that the two maintain optical series connection. At the same time, the transmittance of the optical series layer 14 is set to 95% or more, which can minimize photon transmission loss and allow the photons generated by the radiation recombination layer 13 to be efficiently transmitted to the surface of the solar cell 20 and fully absorbed and utilized. In this way, the carrier multiplication advantage can be fully utilized to improve the photoelectric conversion efficiency of the solar cell 20.

[0061] In some of these embodiments, see Figure 1 As shown, the refractive index of the optical tandem layer 14 is greater than that of the radiation composite layer 13.

[0062] Therefore, by setting the refractive index of the optical tandem layer 14 to be greater than that of the radiative recombination layer 13, a reasonable refractive index gradient can be formed at the interface between the two layers. This enables the total internal reflection of photons generated by the radiative recombination layer 13, reducing photon loss to the outside. More photons are confined and directionally transmitted into the solar cell 20, improving photon utilization. At the same time, it can optimize the optical path transmission, weaken interface light scattering and reflection loss, and ensure that the multiplied photons generated by radiative recombination are efficiently coupled into the solar cell 20, further improving the photoelectric conversion efficiency.

[0063] It should be noted that the light-receiving side of the solar cell 20 has a passivation antireflection layer. The refractive index of the passivation antireflection layer is greater than that of the optical tandem layer 14. This can effectively reduce the reflection loss at the interlayer interface, reduce photon scattering and escape, and enable the photons generated by the radiation composite layer 13 to smoothly penetrate each functional layer and enter the interior of the solar cell 20, thereby further improving the photoelectric conversion efficiency.

[0064] In some of these embodiments, see Figure 1 As shown, the thickness of the optical tandem layer 14 is greater than or equal to 200 nm and less than or equal to 6000 nm.

[0065] It should be noted that, for reference Figure 3 As shown, if the solar cell 20 is a crystalline silicon cell, and the light-receiving side of the crystalline silicon cell has a pyramidal textured surface structure, the thickness of the optical tandem layer 14 is uneven. The distance between the surface of the optical tandem layer 14 near the radiative recombination layer 13 and the top of the pyramid can be greater than or equal to 200 nm and less than or equal to 1000 nm. (See reference...) Figure 3 As shown, if the solar cell 20 is a thin-film cell, the thickness of the optical tandem layer 14 is greater than or equal to 200 nm and less than or equal to 2000 nm, and the optical tandem layer 14 can have a relatively uniform thickness.

[0066] In this embodiment, by making the thickness of the optical tandem layer 14 greater than or equal to 200 nm and less than or equal to 6000 nm, and the thickness not less than 200 nm, a complete and continuous isolation film layer can be formed, so as to achieve reliable electrical insulation between the radiation recombination layer 13 and the solar cell 20, and ensure the optical tandem connection between the radiation recombination layer 13 and the solar cell 20. Controlling the thickness to within 6000 nm can reduce the parasitic absorption of the material itself, reduce the light loss in the photon transmission process, and ensure that the photons generated by radiation recombination are efficiently transmitted to the surface of the battery, thereby improving the photoelectric conversion efficiency.

[0067] In some embodiments, the optical tandem layer 14 is made of nitrogen-doped hafnium oxide (HfO). 1-x N x .

[0068] Therefore, by including nitrogen-doped hafnium oxide in the material of the optical tandem layer 14, the optical tandem layer 14 can have high resistivity and transmittance, ensuring that the radiation recombination layer 13 and the solar cell 20 maintain optical tandem, so that the photons generated by the radiation recombination layer 13 are efficiently transmitted to the surface of the solar cell 20 and fully absorbed and utilized, giving full play to the carrier multiplication advantage and improving the photoelectric conversion efficiency of the solar cell 20.

[0069] In some of these embodiments, see Figure 1As shown, the thickness of the single-line split layer 12 is greater than or equal to 200 nm and less than or equal to 1000 nm.

[0070] Therefore, by limiting the thickness of the singlet split layer 12 to 200 nm to 1000 nm, it is possible to ensure that the singlet split layer 12 has sufficient thickness to fully capture and absorb high-energy photons from the outside, providing a sufficient basis for the singlet splitting effect and achieving effective generation of multiplied carriers. At the same time, it avoids the problem that the triplet exciton transport path is too long due to excessive thickness, making it difficult to diffuse and migrate to the radiative recombination layer 13 for recombination in time. It also avoids the problem of insufficient absorption of high-energy photons and low carrier multiplication efficiency caused by the singlet split layer 12 being too thin. In this way, while ensuring sufficient absorption of high-energy photons, the transport and recombination efficiency of triplet excitons are taken into account, giving full play to the carrier multiplication advantage and improving the photoelectric conversion efficiency of the solar cell 20.

[0071] In some embodiments, the material of the singlet split layer 12 includes one of tetraphenyl, triphenyl, and dipyrrolonaphthidine dione.

[0072] In some embodiments, the refractive index of the encapsulation layer 11 is less than or equal to the refractive index of the optical tandem layer 14.

[0073] Therefore, by making the refractive index of the encapsulation layer 11 less than or equal to the refractive index of the optical tandem layer 14, the interface light reflection and scattering loss can be reduced. This not only facilitates the efficient entry of external incident light into the singlet splitting layer 12 to excite the singlet splitting effect, but also constrains the photons generated by radiative recombination to be directionally transmitted to the battery side, avoiding photon escape loss, optimizing the overall optical path utilization efficiency, and improving the photoelectric conversion efficiency.

[0074] In some of these embodiments, see Figure 1 As shown, the thickness of the encapsulation layer 11 is greater than or equal to 1 μm and less than or equal to 1 mm. Specifically, the thickness of the encapsulation layer 11 can be 1 μm, 20 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1 mm.

[0075] In some embodiments, the material of the encapsulation layer 11 includes at least one of ethylene-vinyl acetate copolymer, polyolefin elastomer, thermoplastic polyolefin, UV-curable adhesive, and silicone polymer.

[0076] Secondly, see Figure 2 and Figure 3As shown, this application provides a photovoltaic cell, including a solar cell 20 and a photovoltaic encapsulation structure 10 as described in any embodiment of the first aspect. The photovoltaic encapsulation structure 10 is disposed on the light-receiving surface of the solar cell 20, and the optical series layer 14 is located between the radiation recombination layer 13 and the light-receiving surface of the solar cell 20. This effectively improves the conversion efficiency of the photovoltaic cell.

[0077] Specifically, the solar cell 20 can be a crystalline silicon cell or a thin-film cell. The crystalline silicon cell can be an interdigitated back contact (IBC), a heterojunction with intrinsic thin film (HJT), a TOPCon (Tunnel Oxide Passivated Contact), a MWT (Metallization wrapthrough), or a PERC (Passivated Emitter and Rear Cell) cell; the thin-film cell can be a perovskite cell.

[0078] The light-receiving surface of solar cell 20 refers to the side of the photovoltaic cell that faces the outside natural light and directly receives the incident radiation of sunlight.

[0079] In one example, there are three fabrication processes for photovoltaic cells. Fabrication process A includes: on the inner side of the already formed encapsulation layer 11 (i.e., the surface closest to the solar cell 20), a singlet split layer 12, a radiation composite layer 13, and an optical tandem layer 14 are sequentially formed by spraying, scraping, printing, or other methods to obtain a photovoltaic encapsulation structure 10. The photovoltaic encapsulation structure 10 is then integrally placed on the light-receiving surface of the solar cell 20. Fabrication process B includes: during the formation of the encapsulation layer 11, an integrated photovoltaic encapsulation structure 10, including the optical tandem layer 14, the radiation composite layer 13, the singlet split layer 12, and the encapsulation layer 11, is formed by online coating, co-extrusion, or other methods. The photovoltaic encapsulation structure 10 is then integrally placed on the light-receiving surface of the solar cell 20. Fabrication process C includes: on the light-receiving surface of the solar cell 20, the optical tandem layer 14, the radiation composite layer 13, the singlet split layer 12, and the encapsulation layer 11 are fabricated layer by layer using wet or dry coating techniques. Any of the above fabrication processes is applicable to different types of solar cells 20 and is not limited thereto. In some optional examples, fabrication processes A and B are suitable for TOPCon cells. Fabrication process C is suitable for heterojunction cells or perovskite cells.

[0080] Thirdly, see Figure 2 and Figure 3As shown, this application provides a photovoltaic module, including a solar cell 20 and a photovoltaic encapsulation structure 10 according to any embodiment of the first aspect. The photovoltaic encapsulation structure 10 is disposed on the light-receiving surface of the solar cell 20, and the optical series layer 14 is located between the radiation composite layer 13 and the light-receiving surface of the solar cell 20. This effectively improves the conversion efficiency of the photovoltaic module.

[0081] Specifically, photovoltaic modules also include a first substrate, a second substrate, a busbar, a solder strip, a junction box, a frame, etc. The first substrate can be glass, and the second substrate can be a backsheet.

[0082] The following examples illustrate the conversion efficiency of different photovoltaic cells or photovoltaic modules in this application.

[0083] Table 1: Parameters of different photovoltaic cells or photovoltaic modules

[0084]

[0085] It should be noted that the raw efficiency in the table above refers to the conversion efficiency of the corresponding type of solar cell without photovoltaic encapsulation structure.

[0086] In Example 1, the solar cell uses an HJT crystalline silicon cell, the optical tandem layer uses nitrogen-doped hafnium oxide, the radiative recombination layer uses lead selenide quantum dots, the singlet split layer uses tetraphenylene oxide, and the encapsulation layer uses POE. It is prepared using either preparation process A or preparation process B. In Example 2, the solar cell uses a perovskite cell, the singlet split layer uses triphenylene oxide, and the materials of the optical tandem layer, radiative recombination layer, and encapsulation layer are the same as in Example 1. It is prepared using either preparation process A or preparation process B. In Example 3, the solar cell uses a TOPCon crystalline silicon cell, the singlet split layer uses dipyrrolonaphthidine dione DPND, and the materials of the optical tandem layer, radiative recombination layer, and encapsulation layer are the same as in Example 1. It is prepared using either preparation process A or preparation process B. In Example 4, the materials of the singlet split layer, optical tandem layer, radiative recombination layer, and encapsulation layer, as well as the type of solar cell, are the same as in Example 1; it is prepared using preparation process C. In Example 5, the materials and solar cell type of the singlet split layer, optical tandem layer, radiative recombination layer, and encapsulation layer are the same as in Example 2; fabrication process C is used. In Example 6, the materials and solar cell type of the singlet split layer, optical tandem layer, radiative recombination layer, and encapsulation layer are the same as in Example 3; fabrication process C is used.

[0087] As shown in Table 1, combining different types of solar cells with photovoltaic encapsulation structures can effectively improve photoelectric conversion efficiency. Therefore, the photovoltaic encapsulation structure in this embodiment, when applied to solar cells, can effectively improve photoelectric conversion efficiency.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A photovoltaic encapsulation structure, characterized in that, include: Encapsulation layer; A single-line split layer is provided on one side of the encapsulation layer; A radiation composite layer is disposed on the side of the single-line split layer opposite to the encapsulation layer; The radiation recombination layer is used to receive and recombine the electron-hole pairs generated by the singlet splitting layer to produce photons. An optical tandem layer is disposed on the side of the radiative recombination layer opposite to the singlet split layer. The optical tandem layer is used to electrically insulate the radiative recombination layer from the solar cell and to allow photons generated by the radiative recombination layer to be transmitted and incident on the solar cell.

2. The photovoltaic encapsulation structure according to claim 1, characterized in that, The internal quantum efficiency of the radiation composite layer is greater than or equal to 95%.

3. The photovoltaic encapsulation structure according to claim 1, characterized in that, The lowest empty orbital energy level of the radiation recombination layer is less than or equal to the energy level of the triplet multiplying electron generated by the singlet splitting layer.

4. The photovoltaic encapsulation structure according to claim 1, characterized in that, The thickness of the radiation composite layer is greater than or equal to 100 nm and less than or equal to 300 nm.

5. The photovoltaic encapsulation structure according to claim 1, characterized in that, The material of the radiation composite layer includes lead selenide quantum dots.

6. The photovoltaic encapsulation structure according to claim 1, characterized in that, The resistivity of the optical tandem layer is greater than or equal to 10. 8 Ω·cm; the transmittance of the optical tandem layer is greater than or equal to 95%.

7. The photovoltaic encapsulation structure according to claim 1, characterized in that, The refractive index of the optical tandem layer is greater than that of the radiation composite layer.

8. The photovoltaic encapsulation structure according to claim 1, characterized in that, The thickness of the optical tandem layer is greater than or equal to 200 nm and less than or equal to 6000 nm.

9. The photovoltaic encapsulation structure according to claim 1, characterized in that, The optical tandem layer is made of nitrogen-doped hafnium oxide.

10. The photovoltaic encapsulation structure according to any one of claims 1 to 9, characterized in that, The thickness of the singlet crack layer is greater than or equal to 200 nm and less than or equal to 1000 nm.

11. The photovoltaic encapsulation structure according to any one of claims 1 to 9, characterized in that, The material of the singlet cleavage layer includes one of tetraphenyl, triphenyl, and dipyrrolonaphthidine dione.

12. The photovoltaic encapsulation structure according to any one of claims 1 to 9, characterized in that, The refractive index of the encapsulation layer is less than or equal to the refractive index of the optical tandem layer.

13. The photovoltaic encapsulation structure according to any one of claims 1 to 9, characterized in that, The thickness of the encapsulation layer is greater than or equal to 1 μm and less than or equal to 1 mm.

14. The photovoltaic encapsulation structure according to any one of claims 1 to 9, characterized in that, The encapsulation layer is made of at least one of ethylene-vinyl acetate copolymer, polyolefin elastomer, thermoplastic polyolefin, UV-curable adhesive, and silicone polymer.

15. A photovoltaic cell, characterized in that, The invention includes a solar cell and a photovoltaic encapsulation structure according to any one of claims 1 to 14, wherein the photovoltaic encapsulation structure is disposed on the light-receiving surface of the solar cell, and the optical tandem layer is located between the radiation recombination layer and the light-receiving surface of the solar cell.

16. A photovoltaic module, characterized in that, The invention includes a solar cell and a photovoltaic encapsulation structure according to any one of claims 1 to 14, wherein the photovoltaic encapsulation structure is disposed on the light-receiving surface of the solar cell, and the optical tandem layer is located between the radiation recombination layer and the light-receiving surface of the solar cell.

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