A Method and Device for Edge Passivation of a Crystalline Silicon / Perovskite Tandem Solar Cell

Abstract

The present invention provides a method and device for edge passivation of a crystalline silicon / perovskite tandem solar cell, belonging to the technical field of perovskite crystalline silicon tandem. Through a combination of laser cutting and low-temperature breaking processes, edge passivation is performed on the cut tandem solar cell, effectively reducing the carrier recombination rate of the laser cutting surface and the edge of the cell, and improving the conversion efficiency and stability of the tandem cell module.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite tandem solar cells, and particularly relates to a method and device for edge passivation of crystalline silicon / perovskite tandem solar cells. Background Art

[0002] Crystalline silicon solar cells are currently the dominant technology in the photovoltaic market, accounting for more than 90% of the global market. However, there is a theoretical limit (Shockley-Queisser limit) for the photoelectric conversion efficiency of crystalline silicon cells, which is approximately 29%. Currently, the efficiency of commercial crystalline silicon cells is usually around 20%, and the efficiency of top laboratory cells is only about 26%, which is relatively close to the theoretical limit. To break through this efficiency bottleneck, researchers have begun to explore tandem cell technologies. Due to its excellent optoelectronic properties, such as high absorption coefficient, adjustable bandgap, and simple manufacturing process, perovskite materials have attracted extensive attention in the photovoltaic field in recent years.

[0003] Perovskite-crystalline silicon tandem cells combine a perovskite absorption layer with a crystalline silicon solar cell. The perovskite absorption layer absorbs the ultraviolet and visible light parts, and the crystalline silicon material absorbs the infrared part, improving the spectral utilization rate, reducing the thermal relaxation loss, and enhancing the device performance. To further improve the performance of perovskite-crystalline silicon tandem cells, an edge passivation process is introduced during the cell preparation process. By adding a passivation layer in the edge region of the cell, the recombination loss at the edge is reduced, thereby improving the efficiency of the cell. Specifically, the principles and necessity of edge passivation mainly include the following aspects:

[0004] 1. Reducing surface recombination: Due to manufacturing processes and surface unevenness, etc., the edge region of a solar cell often has a high surface recombination rate, resulting in the recombination of electrons and holes before reaching the electrodes, reducing the photoelectric conversion efficiency of the cell. By adding a passivation layer in the edge region, the number of surface defect states can be reduced, thereby reducing the recombination rate.

[0005] 2. Improving cell performance: The passivation layer can reduce the carrier loss in the edge region, increase the open-circuit voltage and fill factor of the cell, and ultimately improve the conversion efficiency of the cell.

[0006] 3. Increasing photocurrent: The introduction of the passivation layer reduces the non-radiative recombination loss, enabling more photo-generated carriers to participate in the generation of current, increasing the photocurrent of the cell.

[0007] 4. Preventing cell degradation: Edge passivation can also protect the edge region from the influence of the external environment to a certain extent, reducing the degradation of the cell during long-term use.

[0008] Patent application CN119029054A discloses an edge-passivated crystalline silicon cell, a perovskite / crystalline silicon tandem cell, and their preparation. The crystalline silicon cell provided by the present invention is a cut cell, and a GeSe2 passivation layer is covered on the cut end face. Photo-generated carriers will be restricted inside the crystalline silicon cell, preventing the non-radiative recombination of photo-generated carriers at the cut end face, reducing the charge accumulation at the edge of the crystalline silicon cell, thereby reducing the surface recombination rate of the crystalline silicon cell, and thus improving the photoelectric conversion efficiency of the crystalline silicon cell. However, this invention performs edge passivation after cutting a single-junction cell. Compared with a single-junction cell, the tandem cell adds multiple steps (multiple layers of films). The stacking of multiple layers of films often leads to more serious edge recombination and reduces the service life of the cell. Currently, the efficiency records of tandem cells are often for relatively small laboratory areas, such as 1 cm 2 , and the edge recombination phenomenon is not particularly obvious. In the case of commercial sizes, edge recombination often leads to very serious device performance losses. At the same time, in the aging test of tandem cells, it is also found that perovskite often degrades from the edge.

[0009] Therefore, there is an urgent need for an edge passivation process to solve the edge recombination and large-size commercialization problems of tandem solar cells. Summary of the Invention

[0010] To solve the problem that traditional edge passivation processes are difficult to apply to tandem solar cells, the present invention provides a method and device for edge passivation of a crystalline silicon / perovskite tandem solar cell. By combining laser cutting and low-temperature breaking processes, edge passivation is performed on the cut tandem solar cell, effectively reducing the carrier recombination rate of the laser cut surface and the edge of the cell, and improving the conversion efficiency and stability of the cell module.

[0011] To achieve the above object, the specific solutions provided by the present invention are as follows:

[0012] A method for edge passivation of a crystalline silicon / perovskite tandem solar cell includes the following steps:

[0013] Provide a crystalline silicon / perovskite tandem solar cell, which includes a crystalline silicon bottom cell and a perovskite top cell thereon. Laser cut the surface where the crystalline silicon bottom cell of the tandem cell is located to form a groove on the crystalline silicon bottom cell. Subsequently, place the cut tandem cell in a low-temperature environment for breaking. Stack a number of broken tandem cells with the broken surfaces facing the same direction and place them in a carrier. Place the carrier in a deposition device to form an edge passivation layer on the broken surfaces of the number of tandem cells, and disassemble to obtain a number of edge-passivated tandem cells.

[0014] Further, the crystalline silicon bottom cell can be selected from one of the crystalline silicon cell structures such as PERC cell, topcon cell, or HJT.

[0015] Specifically, the crystalline silicon bottom cell sequentially includes a first metal electrode layer, a first transparent electrode layer, a P-type substrate doping layer, a substrate passivation layer, a silicon substrate, a substrate surface passivation layer, an N-type substrate doping layer, and a tunneling layer from bottom to top; the perovskite top cell includes a hole transport layer, a perovskite layer, a perovskite passivation layer, an electron transport layer, a second transparent electrode layer, a second metal electrode layer, and an antireflection layer sequentially disposed on the crystalline silicon bottom cell.

[0016] In another embodiment, the edge passivation method can also be applied to multi-stack cells, that is, several perovskite middle cells are arranged between the crystalline silicon bottom cell and the perovskite top cell, and the perovskite middle cell can include a middle cell hole transport layer, a middle cell perovskite layer, a middle cell perovskite passivation layer, and a middle cell electron transport layer.

[0017] In this embodiment, when the stacked cell is laser cut, a groove is formed by cutting from the surface of the crystalline silicon bottom cell. By controlling the laser power to be 10 - 120 W, the groove depth does not exceed the thickness of the crystalline silicon bottom cell. In this embodiment, the purpose of laser cutting is mainly to form a scribeline on the crystalline silicon bottom cell, and the etching depth can be precisely controlled to reduce the ablation of the perovskite top cell.

[0018] Preferably, the groove depth is 30% - 90% of the thickness of the crystalline silicon bottom cell.

[0019] In this embodiment, the cooling temperature of the stacked cell after cutting in a low-temperature environment is -15~15°C, the cooling time is 2~30 min, and it is broken after cooling.

[0020] Furthermore, the stacked cell after cutting is moved to a low-temperature environment for cooling, and then the stacked cell is allowed to fall under gravity at a certain height onto a conical splitting table and split into two half-piece stacked cells along the path where the groove is located. In this embodiment, cooling the stacked cell after cutting can, on the one hand, reduce the heat conduction diffusion remaining on the crystalline silicon bottom cell after cutting and avoid damaging the crystal structure of the perovskite thin film due to excessive temperature; on the other hand, it can reduce the elastic strain of the perovskite thin film battery, increase its rigidity, and prevent the formation of an irregular cross-section.

[0021] In this embodiment, a number of individual stacked cells obtained by cutting are stacked so that the laser-cut cross-sections are on the same plane, and the stacked solar cell after stacking is placed on a carrier, clamped and blocked by a baffle, and then an edge passivation layer is formed on the laser-cut cross-section. The edge passivation layer can be prepared by deposition methods such as atomic layer deposition, evaporation, chemical vapor deposition, and magnetron sputtering. The edge passivation layer can be selected from thin films such as alumina, silica, and aluminum nitride, and has a thickness of 5-100 nm.

[0022] Optionally, when depositing by atomic layer deposition, the deposition temperature is controlled at 200 °C; the deposition pressure is 1 torr; the flow rate of TMA is 15000 sccm, the flow rate of water vapor is 15000 sccm, and the flow rate of nitrogen is 30000 sccm to form an edge passivation layer on the cross-section.

[0023] Optionally, when depositing by magnetron sputtering, the chamber pressure is controlled at 0.3-0.6 Pa, the deposition power is 2000 W, and 1000 sccm of Ar is introduced to form an edge passivation layer on the cross-section.

[0024] In this embodiment, the stacked cell with the edge passivation layer deposited is put into an annealing device for annealing, the temperature is set at 80-200 °C, and the annealing time is 10 min-30 min. After annealing, it is disassembled. After subsequent testing, it is packaged into a complete battery module.

[0025] The present invention also provides an edge passivation device for a crystalline silicon / perovskite stacked solar cell, which is applied to the above passivation method and includes a laser cutting machine, a low-temperature breaking machine, a deposition device, and a transmission device. The laser cutting machine and the low-temperature breaking machine are sequentially arranged on the transmission device.

[0026] In this embodiment, the laser cutting machine is composed of components such as a laser system, a cutting platform, a cooling system, and a positioning system. The cutting platform is arranged on the transmission device, and the laser system is arranged above the position of the cutting platform and fixed on the laser cutting machine. The laser system is used to emit high-power laser and adjust the running direction and height of the laser; the cutting platform places the battery sample to be cut and can play a role in fixing the position of the battery sample; the positioning system can assist the laser system to accurately cut the sample and determine the laser cutting path. During the cutting process, the cooling system can be used to control the laser cutting machine to maintain a low-temperature environment and reduce the damage to the battery caused by excessive cutting temperature.

[0027] In this embodiment, the low-temperature breaking machine includes a cooling system, a gantry transportation system, and a conical splitting table. The cooling system controls the internal temperature of the low-temperature breaking machine to be in the range of -15 to 15 °C. The battery sample is clamped by the gantry transportation system and moved to a position above the conical splitting table, and the stacked battery falls to obtain two stacked batteries.

[0028] In this embodiment, the transmission device consists of multiple conveyor belts and a control system. The control system independently controls each of the multiple conveyor belts to transport the sample. Specifically, the multiple conveyor belts include a feeding conveyor belt, a first conveyor belt, and a discharging conveyor belt. The feeding conveyor belt is fixedly connected below the laser cutting machine. The battery sample can be moved into the laser cutting machine through the feeding conveyor belt for cutting. After cutting, it is moved to the low-temperature breaking machine through the first conveyor belt for cooling, and then the battery sample is moved to the conical splitting table by the gantry transportation system for breaking. The conical splitting table is transported out through the discharging conveyor belt. The cut stacked solar cells are collected, stacked, and placed in a carrier, and then placed in a deposition device for edge passivation deposition of the cross-section.

[0029] In this embodiment, the deposition device includes a deposition device gas path system, a vacuum system, and a reaction chamber. Both the vacuum system and the deposition device gas path system are connected to the reaction chamber. The vacuum system controls the air pressure in the reaction chamber to maintain a vacuum environment inside the chamber, and the deposition device gas path system is used to inject the gases required for the reaction into the reaction chamber or extract the useless gases after the reaction.

[0030] In this embodiment, the carrier includes a support frame, at least two fixing rods, and at least two baffles. At least one fixing notch is provided on the fixing rod and fixed to the support frame. The at least two baffles are parallel, and each fixing notch engages with the two baffles. The gap between every two baffles is controlled by the fixing rod to fix the stacked batteries between every two baffles.

[0031] Preferably, the number of the baffles is an even number, the multiple fixing rods are arranged in parallel, and each fixing rod is fixed to the edge of every two baffles in a biting manner through the fixing notch.

[0032] The present application provides a method for edge passivation of a crystalline silicon / perovskite tandem solar cell, which includes laser cutting the tandem cell, then placing the cut tandem cell in a low-temperature environment for breaking, stacking a number of broken tandem cells with the fracture surfaces facing the same direction and placing them in a carrier, placing the carrier in a deposition device, and forming an edge passivation layer on the fracture surfaces of the number of tandem cells. By setting an edge passivation layer on the tandem cell, the edge film of the perovskite cell can be effectively protected, the defects and cutting damage of the edge film can be reduced, and the carrier recombination rate of the cutting surface and the cell edge of the tandem cell can be effectively reduced, thereby improving the photoelectric conversion efficiency and stability of the tandem cell. The present application also uses a passivation device to automate the passivation step, reduce human interference, and improve production quality and efficiency. Description of the Drawings

[0033] Figure 1 It is a step diagram of the method for edge passivation of the crystalline silicon / perovskite tandem solar cell described in the present invention;

[0034] Figure 2 It is a flow chart of the edge passivation of the crystalline silicon / perovskite tandem solar cell described in the present invention;

[0035] Figure 3 It is a schematic structural diagram of the crystalline silicon / perovskite tandem solar cell prepared by the method described in the present invention;

[0036] Figure 4 It is a schematic structural diagram of the multi-tandem solar cell prepared by the method described in the present invention;

[0037] Figure 5 It is a schematic structural diagram of the edge passivation device of the crystalline silicon / perovskite tandem solar cell described in the present invention;

[0038] Figure 6 It is a schematic structural diagram of the deposition device described in the present invention;

[0039] Figure 7 It is a schematic structural diagram of the carrier when no tandem cell is loaded described in the present invention;

[0040] Figure 8 It is a schematic structural diagram of the carrier when loaded with tandem cells described in the present invention.

[0041] The reference numerals in the figure are named as:

[0042] 10. Crystalline silicon bottom cell; 101. First metal electrode layer; 102. First transparent electrode layer; 103. P-type substrate doping layer; 104. Substrate passivation layer; 105. Silicon substrate; 106. Substrate surface passivation layer; 107. N-type substrate doping layer; 108. Tunneling layer;

[0043] 20. Perovskite top cell; 201. Hole transport layer; 202. Perovskite layer; 203. Perovskite passivation layer; 204. Electron transport layer; 205. Second transparent electrode layer; 206. Second metal electrode layer; 207. Anti-reflection layer;

[0044] 21. Perovskite middle cell; 211. Middle cell hole transport layer; 212. Middle cell perovskite layer; 213. Middle cell perovskite passivation layer; 214. Middle cell electron transport layer;

[0045] L1. Groove;

[0046] 30. Edge passivation layer;

[0047] 40. Edge passivation device; 401. Laser cutting machine; 4011. Laser system; 4012. Cutting platform; 403. Low-temperature breaking machine; 4031. Gantry transportation system; 4032. Conical dividing table; 404. Transmission device; 405. Deposition equipment; 4051. Deposition equipment gas path system; 4052. Vacuum system; 4053. Reaction chamber;

[0048] 50. Carrier; 501. Support frame; 502. Fixed rod; 5021. Fixed notch; 503. Baffle. Detailed implementation manners

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0050] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more; the terms "center", "longitudinal", "transverse", "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0051] In the commercial production process of the stacked cell, a large-area preparation process is often used to manufacture the stacked cell. After slicing, since the cell edge is exposed to the air, very serious device defects will occur in the edge region, reducing the photoelectric conversion efficiency and stability of the device. Please refer to Figure 1, an embodiment of the present application provides a method for passivating the edge of a crystalline silicon / perovskite tandem solar cell, which is applied to the production of large-area tandem solar cells. A groove L1 is cut on the surface of the crystalline silicon bottom cell 10 of the tandem cell by means of laser cutting. After cutting, low-temperature breaking is carried out to obtain two tandem cells with half the size of the original cell. A number of broken tandem cells are stacked and then batch edge passivation is carried out. After splitting, a number of tandem cells with edge passivation layers are finally obtained. In the present application, the process combining laser cutting and low-temperature breaking can well protect the perovskite top cell 20 of the tandem cell. Cooling the cut tandem cell, on the one hand, can reduce the heat conduction and diffusion remaining on the crystalline silicon bottom cell 10 after cutting, and avoid damaging the crystal structure of the perovskite thin film due to too high temperature; on the other hand, it can reduce the film elastic strain of the perovskite top cell 20, increase its rigidity, prevent the formation of irregular cross-sections, thereby reducing the surface recombination in the edge region of the device and providing the photoelectric conversion efficiency and stability of the device.

[0052] Please refer to Figures 1 to 4 , an embodiment of the present application provides a method for passivating the edge of a crystalline silicon / perovskite tandem solar cell, including:

[0053] Provide a crystalline silicon / perovskite tandem solar cell, which includes a crystalline silicon bottom cell 10 and a perovskite top cell 20 thereon. Laser cutting is performed on the surface where the crystalline silicon bottom cell 10 of the tandem cell is located to form a groove L1 on the crystalline silicon bottom cell 10. Subsequently, the cut tandem cell is placed in a low-temperature environment for breaking. A number of broken tandem cells are stacked with the fracture surfaces facing the same direction and placed in a carrier. The carrier is placed in a deposition device to form an edge passivation layer 30 on the fracture surfaces of the number of tandem cells, and a number of edge-passivated tandem cells are obtained after splitting.

[0054] Further, the crystalline silicon bottom cell 10 can be selected from one of the crystalline silicon cell structures such as PERC cell, topcon cell or HJT.

[0055] Specifically, the crystalline silicon bottom cell 10 sequentially includes a first metal electrode layer 101, a first transparent electrode layer 102, a P-type substrate doping layer 103, a substrate passivation layer 104, a silicon substrate 105, a substrate surface passivation layer 106, an N-type substrate doping layer 107 and a tunneling layer 108 from bottom to top; the perovskite top cell 20 includes a hole transport layer 201, a perovskite layer 202, a perovskite passivation layer 203, an electron transport layer 204, a second transparent electrode layer 205, a second metal electrode layer 206 and an antireflection layer 207 sequentially disposed on the crystalline silicon bottom cell 10.

[0056] In another embodiment, the edge passivation method can also be applied to a multi-stack cell. That is, a plurality of perovskite middle cells 21 are provided between the crystalline silicon bottom cell 10 and the perovskite top cell 20. The perovskite middle cell 21 may include a middle cell hole transport layer 211, a middle cell perovskite layer 212, a middle cell perovskite passivation layer 213, and a middle cell electron transport layer 214.

[0057] In this embodiment, when the stacked cell is laser cut, a groove L1 is formed by cutting from the surface of the crystalline silicon bottom cell 10. By controlling the laser power to be 10 - 120 W and the groove depth not exceeding the thickness of the crystalline silicon bottom cell 10. In this embodiment, the purpose of laser cutting is mainly to form a scribeline on the crystalline silicon bottom cell 10, and the etching depth can be precisely controlled to reduce the ablation of the perovskite top cell 20. Since the perovskite thin film is more vulnerable to damage caused by high-temperature thermal cutting, laser cutting can be carried out in a low-temperature environment. The stacked cell is placed on a low-temperature cutting platform, and the temperature is controlled at -15°C to 5°C, which can reduce the influence of laser ablation on the perovskite thin film.

[0058] Preferably, the depth of the groove L1 is 30% - 90% of the thickness of the crystalline silicon bottom cell 10.

[0059] In this embodiment, the cooling temperature of the cut stacked cell in a low-temperature environment is -15 - 15°C, the cooling time is 2 - 30 min, and it is broken after cooling.

[0060] Furthermore, the cut stacked cell is moved to a low-temperature environment for cooling, and then the stacked cell is allowed to fall by gravity at a certain height on a conical splitting table and split into two half-piece stacked cells along the path where the groove L1 is located. The height can be controlled at 10 cm - 60 cm. In this embodiment, cooling the cut stacked cell can, on the one hand, reduce the heat conduction diffusion remaining on the crystalline silicon bottom cell 10 after cutting and avoid damaging the crystal structure of the perovskite thin film due to excessive temperature; on the other hand, it can reduce the elastic strain of the perovskite thin film battery, increase its rigidity, and prevent the formation of an irregular cross-section.

[0061] In this embodiment, a plurality of single stacked cells obtained by cutting are stacked so that their laser-cut cross-sections are in the same plane, and the stacked stacked solar cell after stacking is placed on a carrier, clamped and blocked by a baffle, and then an edge passivation layer 30 is formed on the laser-cut cross-section. The edge passivation layer 30 can be prepared by deposition methods such as atomic layer deposition, evaporation, chemical vapor deposition, magnetron sputtering, etc. The edge passivation layer 30 can be selected from thin films such as alumina, silica, aluminum nitride, etc., with a thickness of 5 - 100 nm.

[0062] Optionally, when depositing by atomic layer deposition, the deposition temperature is controlled at 200 °C; the deposition pressure is 1 torr; the flow rate of TMA is 15000 sccm, the flow rate of the water vapor is 15000 sccm, and the flow rate of the nitrogen is 30000 sccm, to form an edge passivation layer 30 on the cross section.

[0063] Optionally, when depositing by magnetron sputtering, the chamber pressure is controlled at 0.3 - 0.6 Pa, the deposition power is 2000 W, and 1000 sccm of Ar is introduced, to form an edge passivation layer 30 on the cross section.

[0064] In this embodiment, the stacked cell with the edge passivation layer 30 deposited thereon is placed in an annealing device for annealing, the temperature is set at 80 - 200 °C, the annealing time is 10 min - 30 min. After annealing, it is disassembled. After subsequent testing, it is encapsulated into a complete battery module.

[0065] The above passivation method is mainly used for the edge passivation of crystalline silicon / perovskite stacked solar cells. The method of laser etching and low-temperature breaking can reduce the ablation damage and flexible damage of the sub-cells in the stacked cell by the high-power laser in the traditional edge passivation process, thereby improving the performance of the stacked cell.

[0066] Please refer to Figure 3 , an embodiment of the present application provides a crystalline silicon / perovskite stacked solar cell, prepared by using the above edge passivation method, including: a crystalline silicon bottom cell 10, a perovskite top cell 20 thereon, and an edge passivation layer 30 provided on the side surfaces of the crystalline silicon bottom cell 10 and the perovskite top cell 20.

[0067] Further, the crystalline silicon bottom cell 10 can be selected from one of the crystalline silicon cell structures such as PERC cell, topcon cell or HJT.

[0068] When applied to a PERC cell, the crystalline silicon bottom cell 10 sequentially includes an aluminum back surface field, a passivation film, a P-type silicon wafer, and an N+ emitter from bottom to top.

[0069] When applied to a topcon cell, the crystalline silicon bottom cell 10 sequentially includes a metal grid line, a p+ emitter passivation film, a p+ emitter, an N-type silicon substrate, an ultra-thin tunneling oxide layer, and a phosphorus-doped polysilicon layer from bottom to top.

[0070] In this embodiment, taking HJT as an example, the crystalline silicon bottom cell 10 sequentially includes a first metal electrode layer 101, a first transparent electrode layer 102, a P-type substrate doping layer 103, a substrate passivation layer 104, a silicon substrate 105, a substrate surface passivation layer 106, an N-type substrate doping layer 107, and a tunneling layer 108 from bottom to top; the perovskite top cell 20 includes a hole transport layer 201, a perovskite layer 202, a perovskite passivation layer 203, an electron transport layer 204, a second transparent electrode layer 205, a second metal electrode layer 206, and an antireflection layer 207 which are sequentially disposed on the crystalline silicon bottom cell 10.

[0071] In this embodiment, the crystalline silicon bottom cell 10 is prepared in the following manner: a substrate passivation layer 104 is prepared on the back surface of the silicon substrate 105, and a P-type substrate doping layer 103 is formed by diffusion of a phosphorus source through the substrate passivation layer 104; a substrate surface passivation layer 106 is prepared on the surface of the silicon substrate 105, and an N-type substrate doping layer 107 and a tunneling layer 108 are formed by diffusion of a nitrogen source through the substrate surface passivation layer 106. A first transparent electrode layer 102 and a first metal electrode layer 101 are sequentially formed on the surface of the P-type substrate doping layer 103, and finally the crystalline silicon bottom cell 10 is obtained.

[0072] In this embodiment, each film layer of the perovskite top cell 20 is sequentially formed on the crystalline silicon bottom cell 10.

[0073] In this embodiment, the hole transport layer 201 is one or more of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly-3-hexylthiophene (P3HT), nickel oxide (NiOx), molybdenum trioxide (MoO3), cuprous iodide (CuI), and cuprous thiocyanate (CuSCN).

[0074] In this embodiment, the composition of the perovskite layer 202 can be of the ABX3 structure, where

[0075] the A site is an organic cation, including CH3NH3 + (MA+), NH2CH=NH2 + (FA+), CH3CH2NH3 + or Cs + or one or more of them;

[0076] the B site is a metal cation, including Pb 2+ , Sn 2+ or one or more of them;

[0077] the X site is a halogen anion, including F - , Cl - , Br - , I - or one or more of them.

[0078] In this embodiment, the composition of the perovskite passivation layer 203 includes one or more of propanediamine iodide, propanediamine bromide (PDADBr), butylammonium chloride (BACl), butylammonium bromide (BABr), butylammonium iodide (BAI), N,N-dimethyl-1,3-propanediamine hydrochloride (DMePDADCl), dodecanediamine bromide (DDDADBr), magnesium fluoride, lithium fluoride (LiF), and sodium fluoride (NaF).

[0079] In this embodiment, the composition of the electron transport layer 204 is one or more of zinc oxide (ZnO), tin dioxide (SnO2), titanium dioxide (TiO2), [6,6]-phenyl C 61 methyl butyrate (PC 61 BM), fullerene (C 60 60), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0080] In this embodiment, the composition of the antireflection layer 207 is one or more of magnesium fluoride, lithium fluoride (LiF), sodium fluoride (NaF), and silicon dioxide (SiO2).

[0081] In this embodiment, the first metal electrode layer 101 and the second metal electrode layer 206 are composed of one or more of silver, gold, copper, aluminum, and carbon.

[0082] In this embodiment, the first transparent electrode layer 102 and the second transparent electrode layer 205 are composed of one of the transparent materials such as ITO and IZO.

[0083] Please refer to Figure 4 , in another embodiment, the above edge passivation method can also be applied to the production of multi-stack solar cells. The structure of the multi-stack solar cell includes: a crystalline silicon bottom cell 10, several perovskite middle cells 21 and perovskite top cells 20 thereon, and an edge passivation layer 30 provided on the sides of the crystalline silicon bottom cell 10, several perovskite middle cells 21, and perovskite top cells 20.

[0084] Please refer to Figures 5 to 8 , the present invention also provides a crystalline silicon / perovskite stacked solar cell edge passivation device 40, which is applied to the above passivation method and includes a laser cutting machine 401, a low-temperature breaking machine 403, a deposition device 405, and a transmission device 404. The laser cutting machine 401 and the low-temperature breaking machine 403 are sequentially arranged on the transmission device 404.

[0085] In this embodiment, the laser cutting machine 401 is composed of components such as a laser system 4011, a cutting platform 4012, a cooling system, and a positioning system. The cutting platform 4012 is arranged on the transmission device 404, and the laser system 4011 is arranged above the position of the cutting platform 4012 and fixed on the laser cutting machine 401. The laser system 4011 is used to emit high-power laser and adjust the running direction and height of the laser; the cutting platform 4012 places the battery sample to be cut and can play a role in fixing the position of the battery sample; the positioning system can assist the laser system to accurately cut the sample, determine the laser cutting path, and during the cutting process, the cooling system can be used to control the laser cutting machine 401 to maintain a low-temperature environment inside, reducing the damage to the battery caused by excessive cutting temperature.

[0086] In this embodiment, the low-temperature breaking machine 403 includes a cooling system, a gantry transportation system 4031, and a conical splitting table 4032. The cooling system controls the inside of the low-temperature breaking machine to be in a low-temperature environment of -15 to 15 °C. The gantry transportation system 4031 clamps the battery sample and moves the sample to the position above the conical splitting table 4032, and the laminated battery falls to obtain two laminated batteries.

[0087] In this embodiment, the transmission device 404 is composed of multiple conveyor belts and a control system. The control system independently controls multiple conveyor belts to perform the transportation work of the sample. Specifically, the multiple conveyor belts include a feeding conveyor belt, a first conveyor belt, and a discharging conveyor belt. The feeding conveyor belt is connected and fixed below the laser cutting machine 401. The battery sample can be moved into the laser cutting machine 401 through the feeding conveyor belt for cutting, and after cutting, it is moved into the low-temperature breaking machine 403 through the first conveyor belt for cooling, and then the battery sample is moved onto the conical splitting table 4032 through the gantry transportation system 4031 for breaking. The conical splitting table 4032 is transported out through the discharging conveyor belt. The collected cut laminated solar cells are stacked and placed in the carrier 50, and then placed in the deposition device 405 for edge passivation deposition work on the cross-section.

[0088] In this embodiment, the deposition device 405 includes a deposition device gas path system 4051, a vacuum system 4052, and a reaction chamber 4053. Both the vacuum system 4052 and the deposition device gas path system 4051 are connected to the reaction chamber 4053. The vacuum system 4052 controls the air pressure in the reaction chamber 4053 to maintain a vacuum environment inside the chamber, and the deposition device gas path system 4051 is used to inject the gases required for the reaction into the reaction chamber 4053 or extract the useless gases after the reaction.

[0089] In another alternative embodiment, the deposition device 405 can passivate not only the fracture surface of the stacked cell, but also the other three cell sides including the fracture surface, further improving the passivation effect of the cell.

[0090] In this embodiment, the carrier 50 includes a support frame 501, at least two fixing rods 502, and at least two baffles 503. At least one fixing notch 5021 is provided on the fixing rod 502 and fixed on the support frame 501. The at least two baffles 503 are parallel, and each fixing notch 5021 engages with the two baffles 503. The gap between every two baffles 503 is controlled by the fixing rod 502 to fix the stacked cells stacked between every two baffles 503.

[0091] Preferably, the number of the baffles 503 is an even number, and the multiple fixing rods 502 are arranged in a parallel relationship. Each fixing rod 502 is fixed to the edges of every two baffles 503 in a biting manner through the fixing notch 5021.

[0092] In an alternative embodiment, the carrier 50 can hold at least two broken stacked cells, and under conditions allowing, can also hold more than 1000 broken stacked cells of an order of magnitude.

[0093] Specific embodiments and comparative examples are provided below to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0094] Example 1

[0095] Step 1: Prepare a number of prepared large-area crystalline silicon / perovskite stacked solar cells. Cells with an area of M6 can be selected according to production needs. The cells include a crystalline silicon bottom cell 10 and a perovskite top cell 20. Place the cells on the conveyor belt with the crystalline silicon bottom cell 10 facing upward and move them to the laser cutting machine 401 for cutting. Control the power of the laser cutting to be 100w to form a groove L1 on the surface of the crystalline silicon bottom cell 10 on the stacked solar cell. The depth of the groove L1 is 40% of the thickness of the crystalline silicon bottom cell.

[0096] Step 2: Move the cut stacked solar cells to the low-temperature breaking machine 403 for cooling. Control the internal temperature of the low-temperature breaking machine 403 to be -10°C and the cooling time to be 15 minutes. After cooling, clamp them to the upper position above the conical dividing table 4032 through the gantry transportation system 4031. Align the cutting groove L1 with the dividing line of the conical dividing table 4032 and drop to obtain two stacked solar cells.

[0097] Step 3: Stack a number of single-layered solar cells after breaking so that their laser-cut cross-sections are on the same plane. Place the stacked solar cells on the carrier 50, clamp and block them with the baffle 503, and then form an aluminum oxide passivation layer with a thickness of 20 nm on the laser-cut cross-section. When depositing the aluminum oxide passivation layer by atomic layer deposition, control the deposition temperature at 200 °C, the deposition pressure at 1 torr, the flow rate of TMA at 15000 sccm, the flow rate of water vapor at 15000 sccm, and the flow rate of nitrogen at 30000 sccm.

[0098] Step 4: Then put the solar cell wafers with aluminum oxide thin film passivated on the edges into an annealing equipment for annealing. Set the temperature at 200 °C and the process time at 20 min. After annealing, sort and test the half cells, and then package them into half cell modules.

[0099] Example 2

[0100] This example is the same as Example 1 in steps, the difference is that the cutting depth of the groove L1 in Step 1 is 60% of the thickness of the crystalline silicon bottom cell 10.

[0101] Example 3

[0102] This example is the same as Example 1 in steps, the difference is that the cutting depth of the groove L1 in Step 1 is 80% of the thickness of the crystalline silicon bottom cell 10.

[0103] Example 4

[0104] This example is the same as Example 2 in steps, the difference is that the cooling temperature of the stacked solar cells after cutting in Step 3 is -15 °C.

[0105] Example 5

[0106] This example is the same as Example 2 in steps, the difference is that the cooling temperature of the stacked solar cells after cutting in Step 3 is -5 °C.

[0107] Example 6

[0108] This example is the same as Example 2 in steps, the difference is that the cooling temperature of the stacked solar cells after cutting in Step 3 is 0 °C.

[0109] Comparative Example 1

[0110] Step 1: Prepare a number of large-area crystalline silicon-perovskite tandem solar cells that have been fabricated. Cells with an area of M6 can be selected according to production requirements. The cell includes a crystalline silicon bottom cell 10 and a perovskite top cell 20. Place the cell on the conveyor belt with the crystalline silicon bottom cell 10 facing up and move it to a laser cutting machine for cutting. Control the laser cutting power to 100w and cut the tandem solar cell to obtain two solar cells.

[0111] Step 2: Stack a number of single tandem solar cells after cutting so that their laser-cut cross-sections are on the same plane. Place the stacked tandem solar cells on a carrier 50 and clamp and block them with a baffle 503. Then, form an aluminum oxide passivation layer with a thickness of 20nm on the laser-cut cross-section. When depositing the aluminum oxide passivation layer using atomic layer deposition, control the deposition temperature to 200°C, the deposition pressure to 1 torr, the flow rate of TMA to 15000 sccm, the flow rate of water vapor to 15000 sccm, and the flow rate of nitrogen to 30000 sccm.

[0112] Step 3: Then, place the solar cell wafers with edge passivated by an aluminum oxide film into an annealing equipment for annealing. Set the temperature to 200°C and the process time to 20 min. After annealing, sort and test the half cells, and then package them into half cell modules.

[0113] Comparative Example 2

[0114] This comparative example is the same as the steps of Example 2, except that in Step 2, the cut tandem solar cells are not cooled and are broken at room temperature.

[0115] Comparative Example 3

[0116] This comparative example is the same as the steps of Comparative Example 1, except that the edge passivation process in Step 2 is removed, and annealing, packaging, and testing are directly performed. The comparative example directly uses the solar cell wafers after laser non-destructive cutting without any repair treatment.

[0117] Test the tandem solar cells obtained in Examples 1-3 and the comparative examples. The test conditions are as follows: Use a solar simulator to perform a standard solar irradiance calibration and conduct a long-term IV test on the example devices with an area of 1.0 cm 2 Set the starting voltage to 1.95V, the cut-off voltage to 0V, and the range to 100mA. The results are retained to one decimal place. The test results are shown in Table 1 below.

[0118] Table 1. Performance test results of the solar cell wafers obtained in Examples 1-6 and the comparative examples

[0119] Performance indicators EFF (%) Voc (V) <![CDATA[ Isc (mA / cm 2 )]]> FF (%) Example 1 24.35 1.811 18.321 73.2 Example 2 24.75 1.815 18.331 74.4 Example 3 24.42 1.813 18.328 73.5 Example 4 24.32 1.806 18.326 73.5 Example 5 24.53 1.814 18.328 73.8 Example 6 24.27 1.807 18.323 73.3 Comparative example 1 22.51 1.731 18.213 71.4 Comparative example 2 23.65 1.786 18.248 72.6 Comparative example 3 23.56 1.783 18.229 72.5

[0120] In Table 1, EFF refers to the battery conversion efficiency, Voc is the open-circuit voltage of the cell, Isc is the short-circuit current of the cell, and FF refers to the fill factor.

[0121] It can be seen from the table that the perovskite / silicon tandem solar cell with edge passivation effectively protects the perovskite solar cell edge film, improves stability, effectively reduces the carrier recombination rate at the laser cutting surface and the edge of the cell, and effectively improves the conversion efficiency of the cell module. Examples 1-3 show that different cutting depths have different effects on the performance of the battery. This is because when the cutting depth is too high, the high temperature during cutting will affect the structure of the perovskite thin film layer, thus reducing the overall battery performance; when the cutting depth is too low, on the one hand, it will affect the structure of the silicon-based battery, and on the other hand, due to the insufficient breaking force required for the perovskite top cell to form a regular cross-section, the obtained battery cross-section structure has defects. In Examples 4-5 and Comparative Example 2, breaking at different temperatures will affect the cross-section regularity of the tandem battery. Cooling the cut tandem battery can, on the one hand, reduce the heat conduction diffusion remaining on the crystalline silicon bottom cell after cutting and avoid damaging the crystal structure of the perovskite thin film due to excessive temperature; on the other hand, it can reduce the elastic strain of the perovskite thin film battery, increase its rigidity, and prevent the formation of an irregular cross-section.

[0122] Comparative Example 1 shows that only using laser to cut the entire perovskite / silicon tandem battery will seriously damage the perovskite thin film structure and reduce its battery photoelectric conversion efficiency and stability. Comparative Example 3 shows that when the passivation process is not carried out after cutting, due to the defects of the cross-section, the surface recombination loss of the battery is serious.

[0123] The above embodiments are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, various changes, modifications, substitutions, and deformations can be made to these embodiments. These technical solutions obtained by equivalent substitution of the claims of the present invention all fall within the protection scope of the present invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for edge passivation of a crystalline silicon / perovskite tandem solar cell, characterized in that: The following steps are involved: A crystalline silicon / perovskite tandem solar cell is provided, the crystalline silicon / perovskite tandem solar cell comprises a crystalline silicon bottom cell and a perovskite top cell thereon, laser cutting is performed on the surface where the crystalline silicon bottom cell of the crystalline silicon / perovskite tandem solar cell is located, a groove is formed on the crystalline silicon bottom cell, the cut crystalline silicon / perovskite tandem solar cell is then placed in a low temperature environment for breaking, a plurality of broken crystalline silicon / perovskite tandem solar cells are stacked with the broken surfaces facing the same direction and placed in a carrier, the carrier is placed in a deposition device, an edge passivation layer is formed on the broken surfaces of the plurality of crystalline silicon / perovskite tandem solar cells, and a plurality of edge-passivated crystalline silicon / perovskite tandem solar cells are split; When the crystalline silicon / perovskite stacked solar cell is laser cut, the surface where the crystalline silicon bottom cell is located is cut to form a groove, and the groove depth does not exceed the thickness of the crystalline silicon bottom cell.

2. The edge passivation method of crystalline silicon / perovskite tandem solar cell according to claim 1, characterized in that: By controlling the laser power to 10~120W.

3. The edge passivation method of crystalline silicon / perovskite tandem solar cell according to claim 2, characterized in that: The groove depth is 30-90% of the thickness of the crystalline silicon bottom cell.

4. The edge passivation method of crystalline silicon / perovskite tandem solar cell according to claim 1, characterized in that: The crystalline silicon / perovskite stacked solar cell after cutting is cooled to a temperature of -15 to 15° C. in a low temperature environment for 2 to 30 minutes, and is broken after cooling.

5. The edge passivation method of crystalline silicon / perovskite tandem solar cell according to claim 1, characterized in that: After cutting, the crystalline silicon / perovskite tandem solar cell is moved to a low-temperature environment for cooling, and then the crystalline silicon / perovskite tandem solar cell falls on a conical dividing table at a certain height due to gravity, and is divided into two half-pieces of crystalline silicon / perovskite tandem solar cell along the path of the groove.

6. The edge passivation method of crystalline silicon / perovskite tandem solar cell according to claim 1, characterized in that: The edge passivation layer is prepared by one of the deposition methods of atomic layer deposition, evaporation, chemical vapor deposition, and magnetron sputtering. The edge passivation layer is selected from one or more thin films of aluminum oxide, silicon oxide, and aluminum nitride, and has a thickness of 5 to 100 nm.

7. The edge passivation method of crystalline silicon / perovskite tandem solar cell according to claim 1, characterized in that: The crystalline silicon / perovskite stacked solar cell with edge passivation layer is placed in an annealing device for annealing, the temperature is set to 80-200°C, the annealing time is 10min~30min, and after the annealing is completed, it is split.

8. The edge passivation method of crystalline silicon / perovskite tandem solar cell according to claim 1, characterized in that: The crystalline silicon bottom cell is selected from one of the crystalline silicon cell structures of PERC cell, topcon cell or HJT; the perovskite top cell includes a hole transport layer, a perovskite layer, a perovskite passivation layer, an electron transport layer, a second transparent electrode layer, a second metal electrode layer and an anti-reflection layer which are sequentially arranged on the crystalline silicon bottom cell.

9. A crystalline silicon / perovskite tandem solar cell edge passivation device, applied to the crystalline silicon / perovskite tandem solar cell edge passivation method according to any one of claims 1 to 8, characterized in that: It comprises a laser cutting machine, a low temperature breaking machine, a deposition device and a transmission device, wherein the laser cutting machine and the low temperature breaking machine are arranged on the transmission device in sequence.

10. The edge passivation device for crystalline silicon / perovskite tandem solar cell according to claim 9, characterized in that: The laser cutting machine is composed of a laser system, a cutting platform, a cooling system, and a positioning system. The cutting platform is arranged on the transmission device, and the laser system is arranged above the cutting platform and fixed on the laser cutting machine.

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