Optical film layer, multi-terminal stacked solar cell and preparation method therefor, battery assembly, and electric device

Abstract

This application discloses an optical film layer, a multi-terminal tandem solar cell, a method for fabricating the same, a battery module, and an electrical device. The multi-terminal tandem solar cell includes a perovskite sub-cell, another sub-cell, and an optical layer. The perovskite sub-cell is positioned at the front end of the incident light path of the other sub-cell. The optical layer is positioned between the perovskite sub-cell and the other sub-cell, and contains dispersed scattering particles and wavelength conversion particles. The multi-terminal tandem solar cell, through its optical layer, allows high-intensity light passing through the "dead zone" of the perovskite sub-cell to diffuse laterally, distributing it to the adjacent "active zone" projection area. This portion of the light is converted into longer-wavelength light for absorption and conversion by the other sub-cell. This effectively improves the spatial uniformity of the light intensity received by the other sub-cell and the light energy utilization rate, while reducing thermal losses. The battery module and electrical device include the multi-terminal tandem solar cell of this application.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, specifically relating to an optical film layer, a multi-terminal stacked solar cell and its preparation method, a battery module and an electrical device. Background Technology

[0002] The rapid industrialization of new high-efficiency photovoltaic technologies, exemplified by tandem solar cells, is driving continuous breakthroughs in module efficiency. Taking perovskite / crystalline silicon tandem solar cells as an example, this structure combines a wide-bandgap perovskite top cell with a narrow-bandgap crystalline silicon bottom cell, enabling both to efficiently absorb short-wave and long-wave solar light respectively. This achieves segmented full utilization of the solar spectrum, theoretically significantly exceeding the efficiency limit of single-junction cells and demonstrating enormous application potential.

[0003] However, in actual component manufacturing and operation, the aforementioned ideal spectral segmentation absorption model faces severe challenges. Due to process requirements, perovskite top cells are typically composed of multiple series-connected sub-cells, and their surfaces inevitably contain "dead zones" (such as cut lines or interconnect regions) and "active zones." The former cannot generate photocurrent, while the latter can effectively generate electricity. This results in a highly uneven spatial distribution of the spectrum and light intensity received by the underlying crystalline silicon cell surface: in the projection region of the "dead zone," the crystalline silicon cell is subjected to intense light irradiation across the entire spectrum, including high-energy short-wavelength light; while in the projection region of the "active zone," only attenuated long-wavelength infrared light is received. This non-uniformity causes local current mismatch and significant microscopic hot spot effects in the crystalline silicon cell, not only resulting in a loss of overall conversion efficiency but also seriously threatening the long-term reliability and stability of the device due to local overheating. Summary of the Invention

[0004] In view of the above problems, this application provides a multi-terminal tandem solar cell and its preparation method, battery module and power device, to solve the technical problem that the spectrum and light intensity received by the surface of the sub-cell at the back end of the optical path of the existing multi-terminal tandem solar cell are extremely uneven in space due to the perovskite sub-cell.

[0005] In a first aspect, embodiments of this application provide a multi-terminal tandem solar cell. The multi-terminal tandem solar cell of this application embodiment includes: Perovskite sub-cells; The other sub-cell, the perovskite sub-cell, is disposed at the front end of the incident optical path of the other sub-cell; An optical layer is disposed between the perovskite sub-cell and the other sub-cell; The optical layer contains scattering particles and wavelength conversion particles.

[0006] This application's multi-terminal tandem solar cell utilizes an optical layer. Wavelength-converting particles in the optical layer convert high-intensity light transmitted through the "dead zone" of the perovskite sub-cell into long-wavelength light. This converts weakly absorbed high-energy photons from the other sub-cell into photons with high absorption efficiency, improving light energy utilization and reducing excessive concentration and thermal loss of high-energy photons in their localized areas. Scattering particles in the optical layer alter the propagation direction of the transmitted light, spatially redistributing it. This causes the short-wavelength light intensity, originally concentrated in the "dead zone" projection area of ​​the other sub-cell, to be laterally diffused to the adjacent "active zone" projection area, fundamentally improving the spatial uniformity of light intensity received by the other sub-cell and reducing its local current mismatch.

[0007] Therefore, through the synergy of spectral optimization and light field redistribution, the optical layer enables the other sub-cell to operate under more uniform and matched spectral conditions. This not only directly improves the local and overall current output and total cell efficiency of the multi-terminal tandem solar cell in the embodiments of this application, but also helps to improve its long-term reliability and stability.

[0008] Furthermore, the volume concentration of the scattering particles and the wavelength conversion particles in the optical layer is 1% to 5%.

[0009] Furthermore, the scattering particles include short-wavelength scattering particles that scatter light with wavelengths of 300 nm to 800 nm.

[0010] Furthermore, the particle size of the scattering particles is 200 nm to 500 nm.

[0011] Furthermore, the scattering particles include at least one of titanium dioxide, silicon dioxide, and zirconium oxide.

[0012] Furthermore, the wavelength conversion particles include long-wavelength conversion particles that convert at least one of ultraviolet and blue light into near-infrared light.

[0013] Furthermore, the wavelength conversion particles have a particle size of 200 nm to 500 nm.

[0014] Furthermore, the wavelength conversion particles include at least one of CsPbBr3 quantum dots, CdSe / ZnS quantum dots, and PbS quantum dots.

[0015] Furthermore, the mass content of the wavelength conversion particles in the optical layer is 0.1% to 2%.

[0016] Furthermore, the thickness of the optical layer is 50 μm to 300 μm.

[0017] Furthermore, the optical layer also includes a substrate, in which scattering particles and wavelength conversion particles are doped, wherein the substrate includes at least one of dimethylsiloxane, ethylene-vinyl acetate copolymer, silicone, and UV-curable adhesive.

[0018] Furthermore, the other sub-cell includes a crystalline silicon sub-cell.

[0019] Furthermore, the multi-terminal tandem solar cell is a four-terminal tandem solar cell.

[0020] Secondly, embodiments of this application provide a method for fabricating a multi-terminal tandem solar cell. The method for fabricating a multi-terminal tandem solar cell includes the following steps: Provide a substrate with at least one sub-cell; The optical layer is prepared on the light-incident surface of the sub-cell; Perovskite sub-cells are fabricated on the light-incident surface of the optical layer.

[0021] The multi-terminal tandem solar cell fabrication method of this application forms an optical layer between the sub-cells of the substrate and the perovskite sub-cells. The wavelength conversion particles in the formed optical layer can convert high-intensity light passing through the "dead zone" of the perovskite sub-cell into long-wavelength light, improving light energy utilization and reducing the risk of hot spots caused by local concentration of high-energy photons from the source. The scattering particles in the formed optical layer can change the direction of light propagation, laterally diffusing the strong light concentrated in the "dead zone" projection area of ​​the other sub-cell to its adjacent "active zone" projection area, improving the uniformity of light intensity distribution on the surface of the other sub-cell 30, and helping to reduce its local current mismatch.

[0022] Thirdly, embodiments of this application also provide an optical film layer. The optical film layer of this application contains scattering particles and wavelength conversion particles.

[0023] The optical film layer in this application embodiment can effectively scatter the light incident upon it and can convert at least a portion of the light into light of other wavelengths.

[0024] Fourthly, embodiments of this application also provide a battery module. The battery module of this application includes a multi-terminal tandem solar cell according to embodiments of this application or a multi-terminal tandem solar cell prepared according to the preparation method of the multi-terminal tandem solar cell according to embodiments of this application.

[0025] Since the battery module of this application embodiment contains the multi-terminal tandem solar cells of the above-described application embodiment, the photoelectric conversion efficiency, long-term operational reliability and stability of the battery module of this application embodiment are improved.

[0026] Fifthly, embodiments of this application also provide an electrical device. The electrical device in this application includes a multi-terminal tandem solar cell or a battery module as described in this application.

[0027] Since the power device in this application embodiment contains the multi-terminal tandem solar cell described in the above application embodiment, the power self-sufficiency, endurance, and reliability of the power device in this application embodiment are improved. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a multi-terminal stacked solar cell according to an embodiment of this application.

[0030] The reference numerals in the detailed embodiments are as follows: 10-Perovskite sub-cell, 20-Optical layer, 30-Another sub-cell. Detailed Implementation

[0031] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0033] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0034] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0035] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0036] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0037] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0038] Against the backdrop of accelerated global energy transition, the photovoltaic industry is experiencing explosive growth. Among them, new high-efficiency photovoltaic technologies, represented by tandem solar cells, are rapidly being industrialized, driving continuous breakthroughs in module efficiency. Taking perovskite / crystalline silicon tandem solar cells as an example, this structure combines a wide-bandgap perovskite top cell with a narrow-bandgap crystalline silicon bottom cell, enabling both to efficiently absorb short-wave and long-wave solar light respectively. This achieves segmented full utilization of the solar spectrum, theoretically significantly exceeding the efficiency limit of single-junction cells, demonstrating enormous application potential.

[0039] However, in actual component manufacturing and operation, the aforementioned ideal spectral segmentation absorption model faces severe challenges. Due to process requirements, perovskite top cells are typically composed of multiple series-connected sub-cells, and their surfaces inevitably contain "dead zones" (such as cut lines or interconnect regions) that cannot generate photocurrent and "active zones" that can generate electricity. These two types of regions have drastically different optical properties: the "active zone" can effectively absorb short-wavelength light from 300nm to 800nm ​​and allow long-wavelength light to pass through; while the "dead zone" has high transmittance across the entire spectrum from 300nm to 1200nm. This difference results in a highly uneven spatial distribution of the spectrum and light intensity received by the underlying crystalline silicon cell surface: in the projection region of the "dead zone," the crystalline silicon cell is subjected to intense full-spectrum light irradiation, including high-energy short-wavelength light; while in the projection region of the "active zone," only attenuated long-wavelength infrared light can be received. This non-uniformity can cause local current mismatch and significant micro hot spot effects in crystalline silicon cells, which not only leads to a loss of overall conversion efficiency, but also seriously threatens the reliability and stability of the device in the long term due to local overheating.

[0040] To address the spectral and intensity unevenness caused by the projection of "dead zones," existing technologies have made several attempts. For example, through precise component design, the projection of the "dead zone" of the perovskite top cell onto the underlying crystalline silicon cell overlaps with areas of the crystalline silicon cell that do not generate photocurrent or have minimal impact (such as metal grid lines). This approach aims to guide areas of intense light irradiation to locations less sensitive to or less damaged by hot spots, thereby mitigating performance degradation caused by hot spot effects to some extent.

[0041] However, existing solutions based on structural alignment have inherent drawbacks. First, this method does not fundamentally eliminate or improve the problem of uneven spectral and energy distribution projected onto the surface of crystalline silicon cells; it merely shifts the location of hot spot risks and fails to achieve active management and effective utilization of ineffective transmitted light energy. Second, achieving precise alignment often places extremely stringent requirements on the patterning design, cutting process, and assembly precision of the top and bottom cells, increasing process complexity and manufacturing costs. More importantly, aligning the high-transmittance "dead zone" with the inactive areas such as the grid lines of the crystalline silicon cell essentially sacrifices the solar energy that could have been utilized in that area. This is equivalent to sacrificing some potential power generation for a limited improvement in reliability, failing to achieve the goal of synergistic optimization of efficiency and stability.

[0042] Therefore, there is an urgent need in the field for a new technological solution that can actively regulate light energy distribution, fundamentally alleviate the spectral unevenness caused by the "dead zone" of the top-mounted solar cell, without sacrificing power generation capacity. In view of the aforementioned shortcomings of existing multi-terminal tandem solar cells, this application proposes the following technical solution.

[0043] Multi-terminal tandem solar cells In a first aspect, embodiments of this application provide a multi-terminal tandem solar cell. In some embodiments, such as Figure 1 As shown, the multi-terminal tandem solar cell of this application embodiment includes a perovskite sub-cell 10, another sub-cell 30, and an optical layer 20; wherein, the perovskite sub-cell 10 is disposed at the front end of the incident light path of the other sub-cell 30; the optical layer 20 is disposed between the perovskite sub-cell 10 and the other sub-cell 30, and the optical layer 20 contains scattering particles and wavelength conversion particles dispersed therein.

[0044] In the embodiments of this application, the perovskite sub-cell 10, optical layer 20 and another sub-cell 30 contained in the multi-terminal tandem solar cell are connected and positioned such that, along the incident direction of the light path, the perovskite sub-cell 10, optical layer 20 and another sub-cell 30 are stacked sequentially.

[0045] Thus, in the multi-terminal tandem solar cell of this application embodiment, the perovskite sub-cell 10 is positioned at the optical path front of another sub-cell 30. After the incident light is absorbed and photoelectrically converted by the perovskite sub-cell 10, it can transmit full-spectrum light from the "dead zone" of the perovskite sub-cell 10, thereby transmitting relatively long-wavelength light from the "active region" of the perovskite sub-cell 10. Since the optical layer 20 is positioned between the perovskite sub-cell 10 and the other sub-cell 30, the light transmitted from the "dead zone" and "active region" of the perovskite sub-cell 10 directly enters the optical layer 20.

[0046] The wavelength conversion particles in the optical layer 20 can efficiently convert the high-intensity ultraviolet / blue light that would otherwise pass directly through the "dead zone" of the perovskite sub-cell 10 into relatively long-wavelength light. This not only converts the low-response high-energy photons of the other sub-cell 30 into long-wavelength photons with the highest absorption efficiency, thus improving the light energy utilization rate, but also reduces the excessive concentration and thermal loss of high-energy short-wavelength light in the local area of ​​the other sub-cell 30, thereby reducing the main heat source that generates microscopic hot spots from the source.

[0047] The scattering particles in the optical layer 20 can change the propagation direction of light transmitted to its surface, spatially redistributing the light that was originally transmitted perpendicularly. This effectively diffuses the short-wavelength light intensity that was originally concentrated in the "dead zone" projection area of ​​the other sub-cell to its adjacent "active zone" projection area. This fundamentally improves the spatial uniformity of the illumination intensity distribution of the other sub-cell 30 and reduces the local current mismatch in the other sub-cell 30.

[0048] Therefore, the multi-terminal tandem solar cell of this application, through the arrangement of the optical layer 20, can leverage the synergistic effect of light scattering and light conversion functions. This not only reduces localized light energy waste and thermal losses, but also, through spectral optimization and light field redistribution, allows the other sub-cell 30 to operate under more uniform and matched spectral conditions overall. This effectively improves the local and overall current output of the other sub-cell 30, thereby directly enhancing the final photoelectric conversion efficiency of the multi-terminal tandem solar cell, while also improving long-term operational reliability and stability.

[0049] Optical layer 20: In some embodiments, the volume concentration of scattering particles contained in the optical layer 20 is 1% to 5%. In exemplary embodiments, it can be a typical but non-limiting content such as 1%, 2%, 3%, 4%, 5%, or any range between two contents.

[0050] Scattering particles with the above-mentioned volume content range can balance the lateral diffusion and relative long-wavelength conversion of high-intensity light transmitted through the optical layer 20 to the "dead zone" of the perovskite sub-cell 10, thereby further improving the spatial uniformity of the light intensity and spectrum of the incident surface of the other sub-cell 30, enhancing the spectral response of the other sub-cell 30 and reducing high-energy photon damage, thereby further synergistically improving the overall photoelectric conversion efficiency and long-term operational reliability and stability of the multi-terminal tandem solar cell of the present application embodiment.

[0051] In some embodiments, the scattering particles in the optical layer 20 include short-wavelength scattering particles capable of scattering light with wavelengths from 300 nm to 800 nm. These short-wavelength scattering particles can effectively enhance the dispersion of high-intensity light waves passing through the "dead zone" of the perovskite sub-cell 10, thereby improving the spatial uniformity of the light intensity and spectrum at the incident surface of the other sub-cell 30, enhancing the spectral response of the other sub-cell 30, and reducing high-energy photon damage.

[0052] In some embodiments, the particle size of the scattering particles in the optical layer 20 can be 200 nm to 500 nm. In exemplary embodiments, these can be typical but non-limiting particle sizes such as 200 nm, 300 nm, 400 nm, and 500 nm, or any range between two particle sizes. In embodiments, the scattering particles include small particle sizes of 200 nm to 300 nm and large particle sizes of 400 nm to 500 nm. In embodiments, when the scattering particles include a mixture of the small and large particle sizes, the mass ratio of the small-diameter scattering particles to the large-diameter scattering particles can be 1:(0.2~1). In exemplary embodiments, this can be 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, etc. Scattering particles with this particle size characteristic can improve the uniformity of their distribution in the optical layer 20, thereby further improving their scattering effect on high-intensity light transmitted from the "dead zone" and improving the spatial uniformity of light intensity and spectrum at the incident surface of the other sub-cell 30.

[0053] In the example, the scattering particles in the optical layer 20 may include at least one of titanium dioxide (TiO2), silicon dioxide (SiO2), and zirconium oxide (ZrO2). These materials have high light transmittance and strong scattering properties.

[0054] In some embodiments, the wavelength conversion particles in the optical layer 20 include long-wavelength conversion particles capable of converting at least one of ultraviolet and blue light into near-infrared light. For example, they can convert 300 nm to 500 nm ultraviolet-blue light into 800 nm to 1100 nm near-infrared light. In this way, the long-wavelength conversion particles can effectively convert high-intensity light transmitted through the "dead zone" of the perovskite sub-cell 10 into long wavelengths, thereby converting the weaker high-energy photons of the other sub-cell 30 into near-infrared photons with the highest absorption efficiency, improving light energy utilization; at the same time, it effectively reduces the excessive concentration and thermal loss of high-energy short-wavelength light in local areas of the other sub-cell 30.

[0055] In some embodiments, the wavelength conversion particles in the optical layer 20 can have a particle size of 200 nm to 500 nm. In exemplary cases, they can be typical but not limiting particle sizes such as 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, and 500 nm, or any range between two particle sizes. Wavelength conversion particles with this particle size range can improve the uniformity of their distribution in the optical layer 20, thereby further improving their conversion efficiency for high-intensity light transmitted from the "dead zone" and improving the light utilization rate of the other sub-cell 30.

[0056] In the example, the wavelength conversion particles in the optical layer 20 may include at least one of CsPbBr3 quantum dots, CdSe / ZnS quantum dots, and PbS quantum dots. These materials can effectively convert short-wavelength light with strong energy into wavelengths such as near-infrared light with relatively long wavelengths, thereby improving the light utilization rate of the other sub-cell 30 and further reducing thermal losses.

[0057] In some embodiments, the wavelength conversion particles contained in the optical layer 20 have a mass content of 0.1% to 2%. In exemplary embodiments, this can be a typical but non-limiting content such as 0.1%, 0.5%, 1%, 1.5%, 2%, or any range between two contents. Wavelength conversion particles within this mass content range can improve their conversion of high intensity to relatively long wavelengths such as near-infrared, and can improve the uniformity of their distribution in the optical layer 20.

[0058] In some embodiments, the optical layer 20 in the above embodiments further includes a substrate in which scattering particles and wavelength conversion particles are doped. In an exemplary embodiment, the substrate includes at least one of transparent dimethylsiloxane (PDMS), ethylene-vinyl acetate copolymer (EVA), silicone, or UV-curable adhesive.

[0059] In some embodiments, the thickness of the optical layer 20 in the above embodiments can be 50 μm to 300 μm, optionally 100 μm to 200 μm. In exemplary cases, it can be a typical but non-limiting content such as 50 μm, 80 μm, 100 μm, 130 μm, 150 μm, 180 μm, 200 μm, 230 μm, 250 μm, 280 μm, 300 μm, or any range between two contents. An optical layer 20 with this thickness range can further improve the light conversion process occurring near the interface, allowing the converted long-wavelength light to enter another sub-cell with the shortest path, minimizing light propagation loss in the medium. Simultaneously, it allows the optical layer 20 to have an appropriate two-dimensional space, enabling scattering particles to effectively "redirect" photons without significantly increasing the longitudinal length of the light path. After scattering in this thin layer, the light can diffuse uniformly laterally to the adjacent "active region" projection area. Therefore, the optical layer 20 with the above-mentioned thickness range can improve the overall efficiency of the multi-terminal stacked solar cell in the present application embodiment and improve the reliability of long-term operation without increasing additional optical loss.

[0060] Perovskite sub-cell 10: In the multi-terminal tandem solar cell of the present application embodiment, the multi-terminal tandem solar cell is composed of two or more sub-cell units, wherein the perovskite sub-cell 10 is one of the key sub-cell units.

[0061] In some embodiments, in the multi-terminal tandem solar cells of this application, the perovskite sub-cells 10 contained in the multi-terminal tandem solar cells can serve as top cells.

[0062] In some embodiments, the perovskite solar cell may include a top electrode, an electron transport layer, a perovskite active layer, a hole transport layer, and a back electrode arranged sequentially along the light path. Other functional layers may also be included, and the specific design can be adjusted according to the needs of the actual application.

[0063] Another sub-battery 30: In some embodiments, in the multi-terminal tandem solar cell of the present application, another sub-cell 30 contained in the multi-terminal tandem solar cell can serve as a bottom cell.

[0064] In some embodiments of the multi-terminal tandem solar cell of this application, the other sub-cell 30 may include a crystalline silicon sub-cell. When the other sub-cell 30 is a crystalline silicon sub-cell, the crystalline silicon sub-cell may be a silicon heterojunction cell (SHJ), a tunnel oxide passivated contact (TOPCon) cell, or other crystalline silicon cells.

[0065] In some embodiments, the multi-terminal tandem solar cells described in the above embodiments of this application can be three-terminal tandem cells, four-terminal tandem cells, or tandem cells with more than four terminals.

[0066] As in the embodiments, the multi-terminal tandem solar cells of the above embodiments of this application include a perovskite sub-cell as the top cell and a crystalline silicon sub-cell as the bottom cell, and the perovskite sub-cell and the crystalline silicon sub-cell constitute a four-terminal tandem cell to meet the application requirements in scenarios that require higher current output or redundant design.

[0067] [Preparation methods for multi-terminal tandem solar cells] Secondly, embodiments of this application provide a method for fabricating the multi-terminal tandem solar cell described in the above-described embodiments. Combined with... Figure 1 The method for fabricating a multi-terminal tandem solar cell according to embodiments of this application includes the following steps: S10: Provides a substrate with at least one electronic component 30; S20: The optical layer 20 is prepared on the light-incident surface of the sub-cell; S30: Fabricate a perovskite sub-cell 10 on the light-incident surface of the optical layer.

[0068] Since the method for fabricating multi-terminal tandem solar cells in this application is used to fabricate the multi-terminal tandem solar cells described in the above application, the optical layer in step S20 contains scattering particles and wavelength conversion particles. Therefore, the outermost sub-cell in step S10 is the other sub-cell 30 contained in the multi-terminal tandem solar cell described in the above application.

[0069] The multi-terminal tandem solar cell fabrication method of this application forms an optical layer 20 between the substrate sub-cell 30 and the perovskite sub-cell 10. Wavelength conversion particles in the optical layer 20 convert high-intensity ultraviolet / blue light passing through the "dead zone" of the perovskite sub-cell 10 into long-wavelength light. This converts high-energy photons that are difficult for the other sub-cell 30 to utilize into photons with high absorption efficiency, improving light energy utilization and reducing the risk of hot spots caused by local concentration of high-energy photons. Simultaneously, scattering particles in the optical layer 20 change the direction of light propagation, laterally diffusing the intense light concentrated in the "dead zone" projection area of ​​the other sub-cell 30 to its adjacent "active zone" projection area. This fundamentally improves the uniformity of light intensity distribution on the surface of the other sub-cell 30, helping to reduce local current mismatch.

[0070] In some embodiments, the method for preparing the optical layer 20 in step S20 may vary depending on the mass ratio, mass content, particle size range, and material type of the scattering particles and wavelength conversion particles in the optical layer 20, as described above in the multi-terminal stacked solar cell embodiments. For the sake of brevity, these details will not be repeated here.

[0071] In some embodiments, the method for preparing the optical layer 20 in step S20 can be coating or deposition. The specific film-forming method can be flexibly selected based on the components contained in the optical layer 20.

[0072] In this embodiment, the optical layer 20 is prepared by a coating method, such as by dispersing scattering particles and wavelength conversion particles in a transparent base film material to form a uniformly dispersed mixture slurry, and then coating the mixture slurry into a film, which is then cured to form the optical layer 20. The base film material can be any type of material used in the optical layer 20 of the multi-terminal tandem solar cell in the above-described embodiments when the substrate is present.

[0073] [Optical Coatings] Thirdly, embodiments of this application also provide an optical film layer. The optical film layer of this application embodiment contains scattering particles and wavelength conversion particles. Therefore, the optical film layer of this application embodiment can effectively scatter light incident upon it and can convert at least a portion of the light into light of other wavelengths.

[0074] In some embodiments, the mass ratio, mass content, particle size range, and material type of the scattering particles and wavelength conversion particles contained in the optical film layer are as described above for the scattering particles and wavelength conversion particles contained in the optical layer 20 of the multi-terminal stacked solar cell in the above-described embodiments. To save space, these details will not be repeated here.

[0075] In some embodiments, the thickness of the optical film layer may also be the thickness of the optical layer 20 of the multi-terminal stacked solar cell in the above-described application embodiments.

[0076] In some embodiments, the optical film layer of this application can be considered as the optical layer 20 of the multi-terminal stacked solar cell of the above-described application embodiments.

[0077] In some embodiments, the optical film layer of this application can be prepared by film formation on the surface of a substrate, such as by preparing the optical layer according to step S20 of the preparation method of the multi-terminal stacked solar cell in the above application embodiment.

[0078] [Battery Components] Fourthly, this application also provides a battery module. The battery module of this application includes the multi-terminal tandem solar cell described in the above-described embodiments, or includes a multi-terminal tandem solar cell prepared by the preparation method of the multi-terminal tandem solar cell described in the above-described embodiments. Therefore, the photoelectric conversion efficiency, long-term operational reliability, and stability of the battery module of this application are all improved.

[0079] [Electrical appliances] Fifthly, this application also provides an electrical device. The electrical device of this application includes a power supply unit, and may also include other auxiliary or necessary components. The power supply unit contains a multi-terminal tandem solar cell or a battery module as described in the above application, used to provide electrical energy. Therefore, the energy autonomy, endurance, and reliability of the electrical device of this application are improved.

[0080] In some embodiments, the power supply may include at least one of a rechargeable power source, a solar-powered electronic device, a solar-powered drone, etc.

[0081] [Example] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0082] Example 1: This embodiment provides a four-terminal stacked solar cell, the structure of which is as follows: Figure 1 As shown, along the light incident direction, the four-terminal tandem solar cell includes a perovskite sub-cell 10 as the top cell, an optical layer 20, and a crystalline silicon bottom cell (another sub-cell 30) as the bottom cell, which are stacked sequentially.

[0083] The fabrication method of a four-terminal tandem solar cell includes the following steps: S1. Fabrication of perovskite solar cell 10: S11: Cleaning the FTO substrate, performing laser P1 scribing on the FTO transparent conductive substrate to form P1 grooves with equal spacing that penetrate the FTO layer; S12: On an FTO glass substrate with P1 lines etched, a FAPbI3 perovskite active layer is prepared sequentially by magnetron sputtering of NiOx and slit coating, followed by C deposition. 60 The NiOx / PSK / C layer was prepared by ALD and then laser P2 scribing to form a through-layer. 60 / P2 groove of SnO2 layer; S13: A transparent conductive TCO layer was prepared by magnetron sputtering, followed by laser P3 scribing to form a layer penetrating NiOx / PSK / C. 60 The P3 grooves in the / SnO2 / TCO layer are laser-cleaned after P3 scribing to facilitate subsequent encapsulation. S2. Fabrication of optical layer 20: S21: CsPbBr3 quantum dots were dispersed in toluene to form a dispersion with a concentration of 10 mg / mL, and ultrasonic treatment was performed for 30 minutes to ensure uniform dispersion. S22: TiO2 scattering particles with a mixed Dv50 particle size of 250nm and 400nm were added to the PDMS prepolymer and mechanically stirred for 2 hours to achieve uniform dispersion, with a total volume concentration of 3% for the scattering particles; S23: Add the quantum dot-toluene dispersion to the PDMS prepolymer containing scattering particles and continue stirring for 1 hour to ensure thorough mixing; S24: Add an appropriate amount of crosslinking agent (5% of the PDMS basis weight) and continue stirring for 30 minutes; S25: The mixed slurry is coated onto the surface of the perovskite top cell using a slot coater, and the wet film thickness is controlled at 250μm. S26: Heat curing at 80°C for 2 hours to form a solid optical layer 20 with a thickness of about 200 μm; wherein, by controlling the mixing ratio of the two dispersions in step S23, the volume concentration of TiO2 scattering particles in the optical layer 20 is 1%, and the mass content of CsPbBr3 quantum dots is 1%, as shown in Example 1 in Table 1 below; S3: Fabrication of a four-terminal tandem solar cell: S31: The backplate glass, lower encapsulating film, crystalline silicon bottom cell, upper encapsulating film, and perovskite top cell 10 with optical layer 20, which are stacked in sequence, are placed into a laminator and hot-pressed after degassing to form a perovskite-crystalline silicon four-terminal stacked module; wherein, the structure of the crystalline silicon bottom cell is front silicon nitride / front alumina / N-type silicon substrate / tunneling oxide layer / doped polycrystalline silicon layer / back silicon nitride (TOPCon).

[0084] Examples 2 to 3: Examples 2 and 3 respectively provide a four-terminal tandem solar cell. Compared with the four-terminal tandem solar cell in Example 1, the content of scattering particles in the optical layer 20 of the four-terminal tandem solar cell in Examples 2 and 3 is different from that in Example 1, as shown in Table 1 below. The rest is the same as in Example 1.

[0085] Comparative Example 1: This comparative example provides a four-terminal tandem solar cell, which differs from the four-terminal tandem solar cell in Example 1 in that: the optical layer 20 contains only scattering particles, that is, it does not contain wavelength conversion particles, as shown in Table 1 below. Everything else is the same as in Example 1.

[0086] Comparative Example 2: This comparative example provides a four-terminal tandem solar cell, which differs from the four-terminal tandem solar cell in Example 1 in that: the optical layer 20 contains only wavelength conversion particles, that is, it does not contain scattering particles, as shown in Table 1 below. Everything else is the same as in Example 1.

[0087] Parameter determination and performance testing of crystalline silicon bottom cells in four-terminal tandem solar cells: The crystalline silicon bottom cells in the four-terminal tandem solar cells of Examples 1 to 7 and Comparative Examples 1 to 2 were measured according to the parameters and performance shown in Table 1 below. The detection methods for each performance are as follows, and the test results are shown in Table 1 below.

[0088] The crystalline silicon bottom cells in the four-terminal tandem solar cells of Examples 1 to 7 and Comparative Examples 1 and 2 were measured according to the parameters and performance shown in Table 1 below. The detection methods for each parameter and performance are as follows, and the test results are shown in Table 1 below.

[0089] Photovoltaic efficiency testing method for crystalline silicon bottom cells in four-terminal tandem solar cells: IV test method; Open-circuit voltage test method for crystalline silicon bottom cells in four-terminal tandem solar cells: IV test method; Short-circuit current test method for crystalline silicon bottom cells in four-terminal tandem solar cells: IV test method; The fill factor (FF) test method for crystalline silicon bottom cells in four-terminal tandem solar cells: IV test method.

[0090] In addition, the test conditions for the above photoelectric efficiency, open-circuit voltage, short-circuit current and fill factor FF are AM1.5G, 1000W / m², 25℃.

[0091] Table 1

[0092] As shown in Table 1, comparing Examples 1 to 3, it can be seen that the device efficiency of the four-terminal tandem solar cell decreases with the increase of the scattering particle content in the optical layer 20. Therefore, appropriately reducing the thickness of the optical layer 20 is beneficial to improving device efficiency. Comparing Examples 1 to 3 with Comparative Examples 1 and 2, it can be seen that the device efficiency of Examples 1 to 3 is significantly better than that of Comparative Examples 1 and 2.

[0093] This indicates that the improved device performance of the four-terminal tandem solar cell demonstrates that the optical layer 20 successfully transferred excess short-wavelength light from the dead zone to the active zone, enhancing the utilization of short-wavelength light by the bottom cell, such as the crystalline silicon cell. The uniformity of the current distribution of the crystalline silicon bottom cell was significantly improved, the microscopic hot spot effect was effectively suppressed, and the stability of the module was significantly enhanced.

[0094] The above embodiments merely illustrate 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 this 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 multi-terminal tandem solar cell, characterized by, include: Perovskite sub-cells; The other sub-cell, the perovskite sub-cell, is disposed at the front end of the incident optical path of the other sub-cell; An optical layer is disposed between the perovskite sub-cell and the other sub-cell; The optical layer contains scattering particles and wavelength conversion particles.

2. The multi-terminal tandem solar cell of claim 1, wherein: The volume concentration of the scattering particles in the optical layer is 1% to 5%.

3. The multi-terminal tandem solar cell of claim 1 or 2, wherein: The scattering particles include short-wavelength scattering particles that scatter light with wavelengths of 300 nm to 800 nm. And / or, the particle size of the scattering particles is 200 nm to 500 nm.

4. The multi-terminal tandem solar cell of claim 3, wherein: The scattering particles include at least one of titanium dioxide, silicon dioxide, and zirconium oxide.

5. The multi-terminal tandem solar cell of any of claims 1, 2, 4, wherein: The wavelength conversion particles include long-wavelength conversion particles that convert at least one of ultraviolet and blue light into near-infrared light; And / or, the wavelength conversion particles have a particle size of 200 nm to 500 nm.

6. The multi-terminal tandem solar cell of claim 5, wherein: The wavelength conversion particles include at least one of CsPbBr3 quantum dots, CdSe / ZnS quantum dots, and PbS quantum dots.

7. The multi-terminal tandem solar cell of any one of claims 1, 2, 4, 6, wherein: The wavelength conversion particles have a mass content of 0.1% to 2% in the optical layer.

8. The multi-terminal tandem solar cell of any one of claims 1, 2, 4, 6, wherein: The thickness of the optical layer is 50 μm to 300 μm; And / or, the optical layer further includes a substrate in which the scattering particles and wavelength conversion particles are doped, wherein the substrate includes at least one of dimethylsiloxane, ethylene-vinyl acetate copolymer, silicone, and UV-curable adhesive.

9. The multi-terminal tandem solar cell of any one of claims 1, 2, 4, 6, wherein: The other sub-cell includes a crystalline silicon sub-cell; And / or, the multi-terminal tandem solar cell is a four-terminal tandem solar cell.

10. The method of producing a multi-terminal tandem solar cell according to any one of claims 1 to 9, wherein Includes the following steps: Provide a substrate with at least one sub-cell; The optical layer is prepared on the light-incident surface of the sub-cell; Perovskite sub-cells are fabricated on the light-incident surface of the optical layer.

11. An optical film layer, characterized in that: The optical film contains scattering particles and wavelength conversion particles.

12. A battery assembly, characterized in that, This includes multi-terminal tandem solar cells as described in any one of claims 1 to 9, or multi-terminal tandem solar cells prepared according to the preparation method described in claim 10.

13. An electrical device, characterized by Includes the multi-terminal tandem solar cell as described in any one of claims 1 to 9 or the battery module as described in claim 12.

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