Solar cell and manufacturing method thereof, laminated cell and photovoltaic module

Abstract

The invention relates to the technical field of solar cells, provides a solar cell and a manufacturing method thereof, a laminated cell and a photovoltaic module, and at least facilitates improvement of contact resistance improvement benefits of a fragmented cell adopting laser-assisted sintering. The manufacturing method comprises the following steps: providing a battery piece, wherein the battery piece comprises a first surface and a second surface which are opposite; forming a first fine grid on the first surface, and forming a second fine grid on the second surface; irradiating the first surface of the battery piece with first laser, and applying first voltage to the first fine grid and the second fine grid; carrying out cutting treatment on the battery piece so as to divide the battery piece into at least two fragmented batteries, and carrying out passivation treatment on the cutting surfaces of the fragmented batteries; irradiating the first surface of at least part of the fragmented battery by using second laser, and applying second voltage to the first fine grid and the second fine grid; wherein the energy density of the second laser is smaller than that of the first laser, and / or the second voltage is smaller than the first voltage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a solar cell, a manufacturing method thereof, a stacked cell and a photovoltaic module. BACKGROUND

[0002] The electrode contact resistance of the surface of a crystalline silicon solar cell has a great influence on the fill factor and conversion efficiency, the lower the contact resistance, the higher the fill factor and conversion efficiency, and thus reducing the contact resistance has become an urgent demand of major cell manufacturers.

[0003] In order to reduce the contact resistance, laser-assisted sintering technology is adopted in the conventional technology, the laser excites the carriers of the cell, and under the action of the reverse bias of the external electric field, the carriers flow directionally to form a loop, when the loop current flows through the metal-semiconductor interface, a relatively obvious thermal effect is generated due to the large contact resistance between the metal and the semiconductor, thereby further promoting the mutual diffusion of the metal and the semiconductor to obtain excellent contact characteristics after sintering.

[0004] However, the improvement of the contact resistance of the split cell by laser-assisted sintering still has a low benefit. SUMMARY

[0005] The embodiments of the present application provide a solar cell, a manufacturing method thereof, a stacked cell and a photovoltaic module, which at least facilitate to improve the improvement benefit of the contact resistance of the split cell by laser-assisted sintering.

[0006] According to some embodiments of the present application, the embodiments of the present application provide a manufacturing method of a solar cell, comprising: providing a cell, the cell comprising a first surface and a second surface opposite to each other; forming a first fine grid on the first surface and a second fine grid on the second surface; irradiating the first surface of the cell with a first laser, and applying a first voltage to the first fine grid and the second fine grid; performing a cutting process on the cell to split the cell into at least two split cells, and performing a passivation process on the cutting surface of the split cell; irradiating the first surface of at least part of the split cells with a second laser, and applying a second voltage to the first fine grid and the second fine grid; wherein the energy density of the second laser is less than the energy density of the first laser, and / or the second voltage is less than the first voltage.

[0007] In some embodiments, after the passivation process, before irradiating the first surface of at least part of the split cells with the second laser and applying the second voltage to the first fine grid and the second fine grid, the method comprises: obtaining an actual contact resistance value of the split cell; if the actual contact resistance value is greater than a preset resistance value, irradiating the first surface of the split cell with the second laser and applying the second voltage to the first fine grid and the second fine grid; if the actual contact resistance value is less than or equal to the preset resistance value, not processing the split cell.

[0008] In some embodiments, after the first surface of the wafer is irradiated by the first laser and the first voltage is applied to the first fine grid and the second fine grid, and before the cutting process is performed, the method comprises: performing a first test on the wafer to obtain a first contact resistance; after the passivation process is performed, before the first surface of the wafer is irradiated by the second laser and the second voltage is applied to the first fine grid and the second fine grid, the method comprises: performing a second test on the wafer to obtain a second contact resistance; obtaining a deviation value of the second contact resistance compared to the first contact resistance; if the deviation value is greater than a target value, irradiating the first surface of the wafer by the second laser and applying the second voltage to the first fine grid and the second fine grid; if the deviation value is less than or equal to the target value, no processing is performed on the wafer.

[0009] In some embodiments, in the first test, the wafer is divided into at least two sub-regions, each sub-region corresponding to a wafer piece, and the first contact resistance represents the contact resistance of the sub-region; in the second test, the second contact resistance represents the contact resistance of the wafer piece.

[0010] In some embodiments, in the step of irradiating the first surface of the wafer by the second laser and applying the second voltage to the first fine grid and the second fine grid, different energy densities of the second laser and different second voltages are selected according to the size of the deviation value.

[0011] In some embodiments, in the first test, the wafer is divided into at least two sub-regions, each sub-region corresponding to a wafer piece, and the first contact resistance represents the contact resistance of a certain number of first fine grids in the sub-region; in the second test, the second contact resistance represents the contact resistance of the first fine grid selected in the first test and the wafer piece.

[0012] In some embodiments, in the step of irradiating the first surface of the wafer by the second laser and applying the second voltage to the first fine grid and the second fine grid, different energy densities of the second laser corresponding to different first fine grids are selected according to the size of the deviation value, and the size of the second voltage applied to different first fine grids on the same wafer piece is the same.

[0013] In some embodiments, in the sub-region, the total number of first fine grids is a first number, and the first contact resistance corresponding to a second number of first fine grids selected in the sub-region is a second number, and the ratio of the second number to the first number is 0.5-1.

[0014] In some embodiments, the first surface of all wafer pieces is irradiated by the second laser and the second voltage is applied to the first fine grid and the second fine grid.

[0015] In some embodiments, the step of irradiating the first surface of the at least partially diced cell with the second laser and applying the second voltage to the first fine grid and the second fine grid further comprises: irradiating a second surface of the at least partially diced cell with a third laser; wherein the third laser has a lower energy density than the second laser.

[0016] In some embodiments, the first laser has a larger spot size than the second laser.

[0017] In some embodiments, after the step of irradiating the first surface of the at least partially diced cell with the second laser and applying the second voltage to the first fine grid and the second fine grid, the method further comprises: irradiating a second surface of the at least partially diced cell with the second laser and applying the second voltage to the first fine grid and the second fine grid.

[0018] According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a solar cell prepared by the manufacturing method of the solar cell in the above-mentioned embodiments.

[0019] According to some embodiments of the present application, still another aspect of the embodiments of the present application further provides a laminated cell, comprising: a perovskite top cell; a crystalline silicon bottom cell, the crystalline silicon bottom cell being the solar cell in the above-mentioned embodiments; and a composite layer, the composite layer being located between the perovskite top cell and the crystalline silicon bottom cell.

[0020] According to some embodiments of the present application, yet another aspect of the embodiments of the present application further provides a photovoltaic module, comprising: at least two cell components, the cell component being the solar cell in the above-mentioned embodiments or the laminated cell in the above-mentioned embodiments; a connecting component, the connecting component being used for connecting adjacent cell components; an adhesive film, the adhesive film covering a surface of the cell component; and a cover plate, the cover plate being located on a side of the adhesive film away from the cell component.

[0021] The technical solutions provided by the embodiments of the present application have at least the following advantages: The method for manufacturing a solar cell provided in the embodiments of the present application comprises the following steps: forming a first fine grid and a second fine grid on a first surface and a second surface of a cell piece respectively; performing laser-assisted sintering on the first fine grid by using a first laser and a first voltage, so that a good ohmic contact is formed between the first fine grid and the cell piece; performing cutting treatment and passivation treatment on the cell piece, so that a plurality of split cell pieces are formed; and performing contact resistance optimization on at least part of the split cell pieces by using a second laser and a second voltage, so that the contact resistance is repaired. BRIEF DESCRIPTION OF DRAWINGS

[0022] One or more embodiments are illustrated by way of example in the figures that form a part of this disclosure and which are illustrative of various embodiments and implementations that can be implemented in accordance with the present application. The figures are not intended to limit the scope of the present application as encompassed by the claims. For the purpose of clarity, not all of the illustrative embodiments can be described in the description and figures. One of ordinary skill in the art can appreciate further variations and modifications in the embodiments disclosed herein.

[0023] Figure 1 A flow chart of a method for manufacturing a solar cell provided in the embodiments of the present application; Figure 2 A structure diagram of each step of a method for manufacturing a solar cell provided in the embodiments of the present application; Figure 3A top view of a battery piece provided by an embodiment of the present application; Figure 4 A top view of a battery piece provided by an embodiment of the present application after being cut into multiple sub-piece batteries; Figure 5 A structural schematic diagram of a stacked battery provided by an embodiment of the present application; Figure 6 A structural schematic diagram of a photovoltaic module provided by an embodiment of the present application.

[0024] Marked for the drawings: 100, battery piece; 101, first surface; 102, second surface; 111, first fine grid; 112, second fine grid; 1001, sub-piece battery; 1002, cutting surface; 10, sub-area; 201, perovskite top battery; 202, crystalline silicon bottom battery; 203, composite layer; 211, electron transport layer; 221, perovskite absorption layer; 231, hole transport layer; 301, battery component; 302, connecting component; 303, adhesive film; 304, cover plate. DETAILED DESCRIPTION

[0025] As known from the background art, the use of laser-assisted sintering to improve the contact resistance of sub-piece batteries still has a low yield.

[0026] Generally, a photovoltaic module includes multiple identical solar cells connected in series and / or in parallel, and the current of the whole solar cell is high, which can easily cause significant resistance loss when flowing through the interconnection elements between the whole solar cells of the photovoltaic module. To improve the problem of large power loss of the whole solar cell, laser cutting technology is used to cut the whole solar cell into half or multiple small sub-piece batteries, and then the sub-piece batteries are connected in series using conductive solder strips. The series current is lower than the whole current, and the decrease of the current of the sub-piece battery can improve the power loss of the photovoltaic module.

[0027] However, during the laser cutting process, the laser partially melts the whole solar cell along a set path, and then the battery piece is cracked along the set path by mechanical force to achieve cutting. This leaves a cutting edge on the sub-piece battery, and the cutting edge forms a laser damage zone and a mechanical fracture zone, which causes the silicon atoms at the cutting edge to lose their original ordered arrangement state. There are a large number of dangling bonds and defect states on the surface, which become effective recombination centers for carriers. A large number of carriers recombine based on the recombination centers, which seriously reduces the photoelectric conversion efficiency of the sub-piece battery. For the cutting surface of the sub-piece battery, a passivation layer is usually formed on the cutting surface to avoid the problem of reduced photoelectric conversion efficiency of the sub-piece battery caused by cutting.

[0028] Generally, the cutting process is performed after the formation of the whole solar cell, at this time, the fine grid on the whole solar cell has been prepared, the contact resistance of the fine grid formed by the laser-assisted sintering technology and the cell piece is low, but after the cutting process and the passivation process, the contact resistance of the fine grid and the cell piece increases, which leads to the small increase of the contact resistance of the split cell, and the efficiency of the split cell also decreases, and the increase of the contact resistance also easily leads to the damage and heating of the photovoltaic module, and the hot spot problem is also aggravated.

[0029] This is because the laser cutting or mechanical cutting will generate huge thermal stress and mechanical stress, which will be transmitted to the fine grid-cell contact interface which has been sintered through the cell piece, leading to the appearance of micro-cracks, lattice distortion or making the originally dense contact loose. Microscopically, this is equivalent to destroying part of the good ohmic contact points that have been formed, increasing the barrier for the carriers to cross the interface, thereby leading to the increase of the contact resistance (Rc). The passivation process often requires a certain heat treatment process, and the temperature curve of this heat treatment process may not match the characteristics of the silver paste, leading to the further oxidation of the silver particles at the interface, the change of the state of the glass powder, or the secondary recrystallization of the metal, which may change the ideal interface morphology formed by the primary sintering, and instead, degrade the performance of some good contact points, increase the non-uniformity and average value of the contact resistance.

[0030] However, if the cutting process and the passivation process are performed on the whole solar cell without forming the fine grid, and then the laser-assisted sintering is used to form the fine grid on the split cell, the manufacturing cost of the fine grid will be doubled.

[0031] The embodiments of the present application provide a solar cell and a manufacturing method thereof, a laminated cell and a photovoltaic module, which at least facilitate the improvement of the increase of the contact resistance of the split cell by laser-assisted sintering.

[0032] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0033] In the description of the embodiments of the present application, the meaning of "a plurality of" is two and more than two, unless otherwise explicitly and specifically limited.

[0034] In this document, the reference to "embodiments" means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean that all the embodiments refer to the same embodiment, nor are they independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] In the description of the embodiments of the present application, the term "and / or" is merely an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of existence of A, existence of A and B, and existence of B. In addition, the character " / " in this paper generally represents that the front and rear associated objects are in an "or" relationship.

[0036] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0037] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components can also be further included.

[0038] The terms used in the description of various described embodiments herein are only used for the description of specific embodiments, and are not intended to be limiting. As used in the description of various embodiments described and the appended claims, "component" is also intended to include the plural form, unless the context clearly indicates otherwise.

[0039] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art can understand that in the embodiments of the present application, many technical details are proposed in order to make the reader better understand the present application. However, the technical solutions claimed by the present application can be realized even without these technical details and various changes and modifications based on the following embodiments.

[0040] Figure 1 A flow chart of a manufacturing method of a solar cell provided by an embodiment of the present application is shown in FIG. 1; Figure 2 A structure schematic diagram corresponding to each step of the manufacturing method of the solar cell provided by the embodiment of the present application is shown in FIG. 2.

[0041] Reference Figure 1 And Figure 2 The manufacturing method of the solar cell provided by the embodiment of the present application comprises: S101, providing a cell piece 100, the cell piece 100 comprising a first surface 101 and a second surface 102 opposite to each other; S102, forming a first fine grid 111 on the first surface 101 and a second fine grid 112 on the second surface 102; S103, using the first laser L1 to irradiate the first surface 101 of the battery piece 100, and inputting a first voltage V1 to the first fine grid 111 and the second fine grid 112, so as to at least laser-assisted sinter the first fine grid 111; S104, performing cutting processing on the battery piece 100, so as to divide the battery piece 100 into at least two split battery pieces 1001, and performing passivation processing on the cutting surface 1002 of the split battery piece 1001; S105, using the second laser L2 to irradiate the first surface 101 of at least part of the split battery piece 1001, and inputting a second voltage V2 to the first fine grid 111 and the second fine grid 112, so as to perform contact resistance optimization on at least part of the split battery piece 1001; wherein the energy density of the second laser L2 is less than the energy density of the first laser L1, and / or the second voltage V2 is less than the first voltage V1.

[0042] For example, the following cases, (1) the energy density of the second laser L2 is less than the energy density of the first laser L1, and the second voltage V2 is less than the first voltage V1; (2) the energy density of the second laser L2 is less than the energy density of the first laser L1, and the second voltage V2 is greater than or equal to the first voltage V1; (3) the second voltage V2 is less than the first voltage V1, and the energy density of the second laser L2 is greater than or equal to the energy density of the first laser L1. That is, at least one of the laser energy or the voltage used in the process of contact resistance optimization needs to be lower than that in the process of laser-assisted sintering, in order to achieve the purpose of gentle repair.

[0043] The manufacturing method of the solar cell provided in the embodiments of the present application includes the following steps: forming a first fine grid and a second fine grid on a first surface and a second surface of a cell piece respectively; performing laser-assisted sintering on the first fine grid by using a first laser and a first voltage, so that a good ohmic contact is formed between the first fine grid and the cell piece; in the process of laser-assisted sintering, carriers are generated in the cell piece by the first laser, and a loop is formed by directional flow by using a second voltage, when the loop current flows through the interface between the first fine grid and the semiconductor in the cell piece, a relatively obvious thermal effect is generated due to the relatively large contact resistance between the metal and the semiconductor, thereby promoting the mutual diffusion of the metal and the semiconductor, so that the first fine grid with excellent contact characteristics after sintering is obtained; then, the cell piece is subjected to cutting treatment and passivation treatment, so as to form a plurality of split cells, since the cutting treatment and the passivation treatment can cause the contact resistance between the first fine grid and the cell piece to decrease, the contact resistance of at least part of the split cells is further optimized by using a second laser and a second voltage, the second laser has a smaller energy density, and / or the second voltage is smaller, so that the contact resistance can be repaired accurately and gently. The second voltage can form an electric field in the split cell, and the glass ions in the silver paste are migrated to the interface again, and the local thermal effect generated by the second laser can perform local annealing on the interface area damaged by stress, so as to repair the micro-cracks and lattice distortion caused by the cutting treatment, and make the metal and the semiconductor re-contact closely. Since a lower energy and / or voltage are used, the process of contact resistance optimization is gentle, and only the contact points whose performance is degraded due to the cutting treatment and the passivation treatment are repaired, and the contact points which still maintain good contact will not be sintered excessively. Compared with the method of performing cutting treatment and passivation treatment first, and then forming fine grids on the split cells by laser-assisted sintering respectively, a large amount of cost can be saved.

[0044] In S101, the cell piece can be any one of a PERC cell (Passivated Emitter and Rear Cell), a PERT cell (Passivated Emitter and Rear Totally-diffused cell), a TOPCon cell (Tunnel Oxide Passivated Contact), and an HJT cell (Heterojunction Technology).

[0045] In some embodiments, the cell piece can be a single-crystal silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-element compound solar cell, and the multi-element compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0046] In some embodiments, one of the first surface or the second surface can serve as a light-receiving surface, and the other of the first surface or the second surface can serve as a back light surface, to form a single-sided cell; in other embodiments, both the first surface and the second surface can serve as light-receiving surfaces, to form a double-sided cell.

[0047] In some embodiments, the first surface or the second surface can have a textured structure, such as a pyramidal texture, so that the textured structure can enhance the absorption and utilization of incident light by the cell, thereby facilitating an increase in the light conversion efficiency of the cell. If the cell is a single-sided cell, a texture can be formed only on one of the first surface or the second surface, and the other of the first surface or the second surface can be a polished surface, which is flatter than the textured surface. It should be noted that for a single-sided cell, a texture can also be formed on both the first surface and the second surface. If the cell is a double-sided cell, a texture can be formed on both the first surface and the second surface.

[0048] In S102, the first fine grid has not yet formed an ohmic contact with the cell, and the second fine grid can have already formed an ohmic contact with the cell, or the second fine grid can also not have formed an ohmic contact with the cell, i.e., the second fine grid is in an under-sintered state. When the second fine grid can not have formed an ohmic contact with the cell, in the subsequent process of laser-assisted sintering, the combined action of the first laser and the first voltage can also promote the sintering of the second fine grid, so that the second fine grid forms an ohmic contact with the cell. The first fine grid is one of a positive fine grid or a negative fine grid, and the second fine grid is the other of the positive fine grid or the negative fine grid.

[0049] In S103, an ohmic contact is formed between the first fine grid and the cell by applying a first voltage between the first fine grid and the second fine grid and irradiating the first surface with a first laser.

[0050] In Figure 2 For example, in the case where the first fine grid is a negative fine grid and the second fine grid is a positive fine grid, the positive terminal of the first voltage is connected to the first fine grid, and the negative terminal of the first voltage is connected to the second fine grid, so that the first voltage forms a reverse bias on the cell.

[0051] In other embodiments, the first fine grid can be a positive fine grid, and the second fine grid can be a negative fine grid, the positive terminal of the first voltage is connected to the second fine grid, and the negative terminal of the first voltage is connected to the first fine grid, so that the first voltage forms a reverse bias on the cell.

[0052] The spot width of the first laser is 100-1500 μm, for example, specifically 100 μm, 300 μm, 500 μm, 800 μm, 1000 μm, 1130 μm, 1250 μm, 1360 μm, 1480 μm or 1500 μm. The spot width of the first laser refers to the maximum distance between any two points on the edge of the spot of the first laser.

[0053] The first laser can sequentially perform laser-assisted sintering on different first fine grids in a scanning manner. The area irradiated by the spot of the first laser covers the first fine grid and part of the area of the first surface near the first fine grid.

[0054] In the Figure 2 In the above embodiment, the first voltage is applied between all the first fine grids and all the second fine grids. In other embodiments, the first voltage can be applied between the first fine grids and the second fine grids in the corresponding area according to the area scanned by the first laser, i.e. the first voltage is applied between the first fine grids and the second fine grids corresponding to the local area subjected to laser-assisted sintering. It should be noted that for the battery piece with the main grid, the first main grid can be further provided on the first surface, and the first main grid is electrically connected with the plurality of first fine grids. The second main grid can be further provided on the second surface, and the second main grid is electrically connected with the plurality of second fine grids. The first voltage can be applied to the first main grid and the second main grid to apply the first voltage to the first fine grids and the second fine grids. If the main grid does not need to be directly electrically connected with the battery piece, the first main grid and the second main grid only serve as electrical transmission, and the first laser will not electrically connect the first main grid (or the first main grid and the second main grid) with the battery piece even if the first laser irradiates the area near the main grid during the laser-assisted sintering process. If the main grid needs to be directly electrically connected with the battery piece, the first laser will also promote the electrical connection between the first main grid (or the first main grid and the second main grid) and the battery piece when the first laser irradiates the area near the main grid during the laser-assisted sintering process. Further, the contact resistance of the first main grid (or the first main grid and the second main grid) can also be optimized in the subsequent contact resistance optimization process.

[0055] For the battery piece without the main grid, the different first fine grids are not electrically connected with each other due to the presence of the main grid, and the different second fine grids are not electrically connected with each other due to the presence of the main grid. Therefore, when the first voltage is applied between the first fine grids and the second fine grids, the first voltage can be applied between only part of the first fine grids and part of the second fine grids, or the first voltage can be applied between all the first fine grids and all the second fine grids.

[0056] Regardless of whether the voltage is applied to the main grid or the fine grid, the voltage can be applied by means of a pressing needle or a metal wire.

[0057] The spot shape of the first laser can be circular, elliptical or other shapes.

[0058] The pulse width of the first laser can be 0.1 ns to 500 ns, for example, specifically 0.1 ns, 0.5 ns, 1 ns, 5 ns, 10 ns, 60 ns, 100 ns, 150 ns, 240 ns, 350 ns, 460 ns, or 500 ns.

[0059] The wavelength of the first laser can be 300 nm to 1200 nm, for example, specifically 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, or 1200 nm.

[0060] The energy density of the first laser can be 20 J / cm 2 to 60 J / cm 2 , for example, specifically 20 J / cm 2 , 25 J / cm 2 , 30 J / cm 2 , 35 J / cm 2 , 40 J / cm 2 , 45 J / cm 2 , 50 J / cm 2 , 55 J / cm 2 , or 60 J / cm 2 .

[0061] The first voltage can be 10 V to 30 V, for example, specifically 10 V, 15 V, 20 V, 25 V, or 30 V.

[0062] In S104, the cutting process divides the battery sheet into at least two split batteries, for example, specifically 2 splits, 3 splits, 4 splits, 6 splits, or 8 splits, etc. The areas of different split batteries can be the same or different.

[0063] The cutting process can use laser cutting technology, non-destructive laser cleaving technology, thermal gasification and thermal melting technology, laser-induced scoring separation technology. Laser cutting technology is to use a high-power laser beam to irradiate the battery sheet, which rapidly heats it to a high temperature, causing the material to melt or vaporize, thereby forming a cutting seam. Non-destructive laser cleaving technology is to locally and rapidly heat the battery sheet by laser, generating a non-uniform temperature field, inducing thermal stress, thereby causing the material to break. Thermal gasification and thermal melting technology is to use a laser beam to directly irradiate the battery sheet during the cutting process, causing the material on the battery sheet to rapidly gasify and melt, forming a cut. Laser-induced scoring separation technology is to form a small notch on the battery sheet, and then inject a liquid to separate the battery sheet along the notch.

[0064] The passivation process includes forming a passivation layer on the cutting surface, and the material of the passivation layer includes silicon oxide, aluminum oxide, silicon nitride, or amorphous silicon, etc.

[0065] The process of forming the passivation layer includes atomic layer deposition, chemical vapor deposition, physical vapor deposition, or plasma-enhanced chemical vapor deposition.

[0066] After the passivation layer is formed on the cutting surface, the passivation process further includes annealing and cooling. The annealing temperature can be 220-240°C, such as 220°C, 225°C, 230°C, 235°C, or 240°C, etc.; the annealing duration can be 10-15 min, such as 10 min, 11 min, 12 min, 13 min, 14 min, or 15 min, etc. The cooling can be by air cooling or natural cooling, so that the sliced battery cools to room temperature (about 25°C), and the cooling duration is usually 15-20 min, such as 15 min, 16 min, 17 min, 18 min, 19 min, or 20 min, etc.

[0067] In S105, the contact resistance increase caused by the cutting process and the passivation process is repaired using a second laser and a second voltage, so that the contact resistance between the first fine grid and the battery piece is reduced again. The energy density of the second laser is less than or equal to the energy density of the first laser, and / or the second voltage is less than the first voltage, which can accurately and gently repair the contact points that have degraded in performance due to the cutting process and the passivation process, and avoid excessive sintering of those still good contact points.

[0068] In some embodiments, the spot size of the first laser is larger than the spot size of the second laser. Since the entire first fine grid on the whole battery piece needs to be sintered in the process of laser-assisted sintering, a larger spot size of the first laser is beneficial to improve the efficiency of laser-assisted sintering; in the process of contact resistance optimization, the performance-degraded contact points need to be optimized accurately, and the area to be irradiated is relatively small, so the second laser can use a smaller spot size.

[0069] The spot width of the second laser is 10-500 μm, for example, specifically 10 μm, 30 μm, 50 μm, 80 μm, 100 μm, 148 μm, 200 μm, 260 μm, 300 μm, 340 μm, 400 μm, 450 μm, or 500 μm. The spot width of the second laser refers to the maximum distance between any two points on the edge of the spot of the second laser.

[0070] The second laser can use a scanning mode to sequentially optimize the contact resistance of different first fine grids, and the area irradiated by the spot of the second laser covers part of the area of the first surface near the first fine grid.

[0071] The spot shape of the second laser can be circular, elliptical, or other shapes.

[0072] The pulse width of the second laser can be 0.1 ns to 500 ns, for example specifically 0.1 ns, 0.5 ns, 1 ns, 5 ns, 10 ns, 60 ns, 100 ns, 150 ns, 240 ns, 350 ns, 460 ns, or 500 ns.

[0073] The wavelength of the second laser can be 300 nm to 1200 nm, for example specifically 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, or 1200 nm.

[0074] The energy density of the second laser can be 1 J / cm 2 to 30 J / cm 2 , for example specifically 1 J / cm 2 , 3 J / cm 2 , 5 J / cm 2 , 10 J / cm 2 , 15 J / cm 2 , 20 J / cm 2 , 25 J / cm 2 , or 30 J / cm 2 .

[0075] In some embodiments, the wavelength of the first laser is the same as the wavelength of the second laser. This can improve the repeatability and reliability of the process, avoiding the absorption uncertainty caused by the first laser and the second laser using different wavelengths. The same wavelength ensures that the laser energy will be preferentially absorbed by the same material, which allows the contact resistance optimization to precisely act on the interface region formed by the laser-assisted sintering, rather than elsewhere. At the same time, the same wavelength of the first laser and the second laser can complete the laser-assisted sintering and the contact resistance optimization on the same equipment, without the need for physical switching or optical path calibration between the two lasers, saving the conversion time between processes, improving the production rhythm and overall capacity. In addition, it can greatly reduce the variables and complexity of experiments, accelerating the process maturation cycle.

[0076] The second voltage can be 5 V to 20 V, for example specifically 5 V, 8 V, 10 V, 13 V, 15 V, 17 V, or 20 V.

[0077] In some embodiments, after the step of irradiating the first surface of the at least partially diced cell with the second laser and applying the second voltage to the first fine grid and the second fine grid, the method further comprises: irradiating the second surface of the at least partially diced cell with the second laser and applying the second voltage to the first fine grid and the second fine grid. In this way, the second fine grid on the second surface can also be subjected to contact resistance optimization to repair the defects of increased contact resistance between the second fine grid and the cell piece caused by the cutting process and the passivation process.

[0078] For example, the first surface is first irradiated with the second laser while the second voltage is applied to the first fine grid and the second fine grid; then the diced cell is flipped over, the second surface is irradiated with the second laser while the second voltage is applied to the first fine grid and the second fine grid, so that the first fine grid and the second fine grid are subjected to contact resistance optimization in sequence. In this way, no additional laser equipment is needed.

[0079] During the irradiation of the second surface with the second laser, the second laser can irradiate different second fine grids in sequence in a scanning manner, and the area irradiated by the spot of the second laser covers part of the area of the second surface near the second fine grid.

[0080] In other embodiments, during the step of irradiating the first surface of the at least partially diced cell with the second laser and applying the second voltage to the first fine grid and the second fine grid, the method further comprises: irradiating the second surface with a third laser; wherein the energy density of the third laser is lower than the energy density of the second laser. The simultaneous action of the third laser and the second voltage can repair the defects of increased contact resistance between the second fine grid and the cell piece caused by the cutting process and the passivation process.

[0081] For example, the first surface is irradiated with the second laser while the second surface is irradiated with the third laser, and the second voltage is applied to the first fine grid and the second fine grid, so that the first fine grid and the second fine grid are subjected to contact resistance optimization at the same time. In this way, the efficiency of contact resistance optimization can be improved. Since the first surface and the second surface are irradiated by the second laser and the third laser respectively, the energy density of the third laser needs to be lower (compared with the energy density of the second laser) under the joint action of the two lasers to avoid excessive sintering of the second fine grid.

[0082] During the irradiation of the second surface with the third laser, the third laser can irradiate different second fine grids in sequence in a scanning manner, and the area irradiated by the spot of the third laser covers part of the area of the second surface near the second fine grid.

[0083] In some embodiments, the orthographic projection of the second laser on the first surface and the orthographic projection of the third laser on the first surface can overlap, so that the first fine grid and the second fine grid in the same area of the diced cell can be subjected to contact resistance optimization at the same time.

[0084] In some embodiments, the second voltage is applied between all the first fine grids and all the second fine grids. In other embodiments, the second voltage can be applied between the first fine grids and the second fine grids in the areas scanned by the second laser or the third laser, or between the first fine grids and / or the second fine grids in need of contact resistance optimization. Figure 2 The specific way of applying the second voltage to the first fine grids and the second fine grids can refer to the way of applying the first voltage to the first fine grids and the second fine grids as described above, which will not be repeated here.

[0085] In some embodiments, the second laser is used to irradiate the first surface of at least part of the sliced cells, and the second voltage is applied to the first fine grids and the second fine grids, i.e. part of the sliced cells are selected for contact resistance optimization. In other embodiments, the second laser is used to irradiate the first surface of all the sliced cells, and the second voltage is applied to the first fine grids and the second fine grids, i.e. all the sliced cells are directly subjected to contact resistance optimization.

[0086] The following will be described with respect to selecting part of the sliced cells for contact resistance optimization.

[0087] As an example of selecting the sliced cells before S105, the specific steps can include: obtaining the actual contact resistance value of the sliced cells; if the actual contact resistance value is greater than the preset resistance value, the sliced cells are subjected to contact resistance optimization; if the actual contact resistance value is less than or equal to the preset resistance value, the sliced cells are not subjected to contact resistance optimization. The sliced cells in need of contact resistance optimization are selected according to the preset resistance value for contact resistance optimization, which can save the step of contact resistance optimization and improve the production rhythm and capacity.

[0088] In some embodiments, the preset resistance value can be the contact resistance value of the cell after laser-assisted sintering. If the contact resistance of the sliced cells does not increase, the sliced cells can not be subjected to contact resistance optimization, and only the sliced cells with increased contact resistance due to cutting and passivation processing can be subjected to contact resistance optimization.

[0089] In other embodiments, the preset resistance value can also be the contact resistance value of the sliced cells under the condition of meeting the preset conversion efficiency. If the contact resistance of the sliced cells can meet a higher conversion efficiency even if it increases, the sliced cells can not be subjected to contact resistance optimization, and only the sliced cells with lower conversion efficiency benefits can be subjected to contact resistance optimization.

[0090] In other embodiments, the preset resistance value can also be the contact resistance value of the sliced cells under the condition of meeting the preset conversion efficiency. If the contact resistance of the sliced cells can meet a higher conversion efficiency even if it increases, the sliced cells can not be subjected to contact resistance optimization, and only the sliced cells with lower conversion efficiency benefits can be subjected to contact resistance optimization.

[0091] As another example of screening the sliced battery before S105, the specific steps can be: after laser-assisted sintering and before cutting processing, the battery piece is subjected to a first test to obtain a first contact resistance; after passivation processing and before contact resistance optimization, the sliced battery is subjected to a second test to obtain a second contact resistance; the contact resistance optimization is performed on at least part of the sliced battery, which can specifically include: obtaining a deviation value of the second contact resistance compared to the first contact resistance; if the deviation value is greater than a target value, the contact resistance optimization is performed; if the deviation value is less than or equal to the target value, the contact resistance optimization is not performed.

[0092] That is, the deviation value of the first contact resistance of the battery piece after laser-assisted sintering and the second contact resistance of the sliced battery after cutting processing and passivation processing is used to determine whether the contact resistance of the sliced battery is increased due to the cutting processing and the passivation processing. If the contact resistance is not increased or the degree of increase is within a suitable range, the contact resistance optimization can not be performed, and only the sliced battery with a relatively obvious increase in contact resistance needs to be subjected to the contact resistance optimization.

[0093] The target value can be calculated according to the allowed increase of the contact resistance, for example, if the contact resistance of the sliced battery is allowed to increase to 1.2 times of the first contact resistance, the target value can be set to 0.2 times of the first contact resistance.

[0094] Figure 3 A top view of a battery piece provided by an embodiment of the present application; Figure 4 A top view of a battery piece provided by an embodiment of the present application after being cut into a plurality of sliced batteries.

[0095] Combined reference Figure 3 And Figure 4 In some embodiments, in the first test (before cutting processing and passivation processing), the battery piece 100 is divided into at least two sub-regions 10 according to the cutting line S, each sub-region 10 corresponds to a sliced battery 1001 after cutting processing and passivation processing, and the first contact resistance represents the contact resistance of the sub-region 10; in the second test (after cutting processing and passivation processing), the second contact resistance represents the contact resistance of the sliced battery 1001. That is, the first test and the second test take the sliced battery as a test unit to determine whether the contact resistance of a single sliced battery is increased due to cutting processing and passivation processing.

[0096] It can be understood that the cutting processing and the passivation processing have different effects on different regions of the battery piece, and the contact resistances of different sliced batteries are affected to different degrees. Taking a single sliced battery as a test unit, the contact resistance optimization can be performed on the contact resistance changes of each sliced battery.

[0097] Further, in the step of contact resistance optimization, according to the size of the deviation value, the energy density of the second laser and the second voltage are selected to select the respective appropriate second laser energy density and second voltage for the sub-battery with different contact resistance rising degrees. If the deviation value is large, it indicates that the single sub-battery is greatly affected by the cutting process and the passivation process, and compared with other sub-batteries, a relatively large second laser energy density and second voltage are needed for contact resistance optimization to improve the repair degree; if the deviation value is small, it indicates that the single sub-battery is less affected by the cutting process and the passivation process, and compared with other sub-batteries, a relatively small second laser energy density and second voltage are needed for contact resistance optimization.

[0098] For example, the energy density range of the second laser is divided into a first energy range and a second energy range, the maximum value of the first energy range is equal to the minimum value of the second energy range; the range of the second voltage is divided into a first voltage range and a second voltage range, the maximum value of the first voltage range is equal to the minimum value of the second voltage range. If the difference between the second contact resistance and the first contact resistance is within the first range, the value in the first energy range is selected as the energy density of the second laser, and the value in the first voltage range is selected as the size of the second voltage for contact resistance optimization; if the difference between the second contact resistance and the first contact resistance is within the second range, the value in the second energy range is selected as the energy density of the second laser, and the value in the second voltage range is selected as the size of the second voltage. Wherein, the minimum value of the first range is equal to the maximum value of the second range.

[0099] In combination with reference Figure 3 and Figure 4 In some other embodiments, in the first test (before the cutting process and the passivation process), the battery piece 100 is divided into at least two sub-regions 10 according to the cutting line S, each sub-region 10 corresponds to a sub-battery 1001 after the cutting process and the passivation process, and the first contact resistance is characterized by the contact resistance of each first fine grid 111 on the sub-region 10 with the battery piece; in the second test, the second contact resistance is characterized by the contact resistance of each first fine grid 111 selected in the first test with the sub-battery 1001. That is, the first test and the second test take a single first fine grid as a test unit, and according to whether the contact resistance of the single first fine grid is increased due to the cutting process and the passivation process, it is determined whether the sub-battery needs to be optimized for contact resistance.

[0100] It can be understood that the cutting process and the passivation process have different effects on different regions of the battery piece, and the contact resistances of different first fine grids are affected to different degrees. Taking a single first fine grid as a test unit, the contact resistance of each single first fine grid can be selected for contact resistance optimization of the sub-battery.

[0101] For example, referring to Figure 3 In the first test, the selected first fine grids are 111a, 111b, 111c, 111d, 111e, 111f, and the first contact resistances are the contact resistance values corresponding to the lengths of 111a, 111b, 111c, 111d, 111e, 111f in each sub-region 10. Since Figure 3 The two sub-regions 10 arranged in the upper and lower positions have the same size, and thus, when testing the first contact resistances corresponding to 111a, 111b, 111c respectively in the left upper corner sub-region 10, the length of the first fine grid tested is divided by the cutting line S, and only the contact resistance values corresponding to 111a, 111b, 111c respectively located above the cutting line S are tested as the first contact resistance values. The testing method of the first contact resistances corresponding to the selected first fine grids in other sub-regions 10 is the same. Referring to Figure 4 In the second test, the second contact resistances corresponding to 111a, 111b, 111c, 111d, 111e, 111f respectively are obtained on each sub-cell 1001.

[0102] Further, in the step of contact resistance optimization, according to the size of the deviation value, the energy density of the second laser corresponding to different first fine grids is selected, and the size of the second voltage used by different first fine grids on the same sub-cell is the same. In the process of contact resistance optimization for the sub-cell, the contact resistance optimization is performed for the first fine grid that needs to be repaired with a single first fine grid as a unit, and the contact resistance optimization does not need to be performed for all first fine grids of the entire sub-cell. The second voltage is input as a unit of the entire sub-cell, and the second voltage input between different first fine grids and second fine grids is the same, and only the energy density of the corresponding second laser needs to be selected for different first fine grids, so that the efficiency of the contact resistance optimization can be improved. If the deviation value is large, it indicates that the single first fine grid is greatly affected by the cutting and passivation processes, and a relatively large second laser energy density is needed for the contact resistance optimization compared with other first fine grids to improve the repair degree. If the deviation value is small, it indicates that the single first fine grid is less affected by the cutting and passivation processes, and a relatively small second laser energy density is needed for the contact resistance optimization compared with other first fine grids.

[0103] In the above embodiment, for convenience of description, the number of selected first fine grids in each sub-region is taken as 3.

[0104] In some embodiments, in the sub-region, the total number of the first fine grids is the first number, and the second number of the first fine grids selected in the sub-region corresponds to the first contact resistance, and the ratio of the second number to the first number is 0.5-1. That is, at least half of the number of the first fine grids on the split battery is selected for the corresponding first test and second test, and the other first fine grids are not tested and do not perform contact resistance optimization. Since the number of fine grids on the battery piece is large, at least half of the number of the first fine grids is selected for the first test and the second test, and the contact resistance is optimized, which can improve the production rhythm and capacity, while ensuring that the overall contact resistance of the split battery can be effectively repaired.

[0105] The test of the contact resistance can adopt the TLM method (Transmission Line Method), which is a method for measuring the contact resistance of electronic devices. The basic principle is to use the transmission line theory to calculate the contact resistance by measuring the voltage and current on the device pins.

[0106] In Figure 3 and Figure 4 , the battery piece 100 is cut into four split batteries 1001 of the same size as an example. In other embodiments, the number of split batteries cut from the battery piece can be 2, 3, 5, 8, or 10, and the sizes of different split batteries can also be different. The division method of the first test and the second test can be adjusted accordingly in combination with the above embodiments.

[0107] In Figure 3 and Figure 4 , two cutting lines perpendicular to each other are taken as an example for illustration, which does not constitute a limitation on the direction and number of cutting lines. In other embodiments, taking four splits as an example, the number of cutting lines can be three, and the three cutting lines can be parallel to each other to divide the battery piece into four split batteries of the same length.

[0108] The manufacturing method of the solar cell provided in the embodiments of the present application includes the following steps: forming a first fine grid and a second fine grid on a first surface and a second surface of a cell piece respectively, performing laser-assisted sintering on the first fine grid by using a first laser and a first voltage, so that a good ohmic contact is formed between the first fine grid and the cell piece. In the process of laser-assisted sintering, the first laser is used to excite the cell piece to generate carriers, and a second voltage is used to form a loop for directional flow. When the loop current flows through the interface between the first fine grid and the semiconductor in the cell piece, a relatively obvious thermal effect is generated due to the large contact resistance between the metal and the semiconductor, thereby promoting the mutual diffusion of the metal and the semiconductor, so that the first fine grid with excellent contact characteristics after sintering is obtained. Then, the cell piece is subjected to cutting treatment and passivation treatment, so as to form a plurality of split cell pieces. Since the cutting treatment and the passivation treatment can cause the contact resistance between the first fine grid and the cell piece to decrease, the second laser and the second voltage are further used to optimize the contact resistance of at least part of the split cell pieces. The second laser has a smaller energy density, and / or the second voltage is smaller, so that the contact resistance can be repaired accurately and gently. The second voltage can form an electric field in the split cell piece, so as to drive the glass ions in the silver paste to migrate to the interface again. In combination with the local thermal effect generated by the second laser, the interface area damaged by stress can be locally annealed, the micro-cracks and lattice distortion caused by the cutting treatment are repaired, and the metal and the semiconductor are in close contact again. Since a lower energy and / or voltage are used, the process of contact resistance optimization is gentle, and only the contact points whose performance is degraded due to the cutting treatment and the passivation treatment are repaired, without causing excessive sintering of the contact points which still maintain good contact. Compared with the method of performing the cutting treatment and the passivation treatment first, and then forming the fine grid by using laser-assisted sintering on the split cell piece, a large amount of cost can be saved.

[0109] According to one specific embodiment of the present application: after the first fine grid with a line width of 8.86 μm and a line height of 18.7 μm is formed on the cell piece, the first laser and the first voltage are used to perform laser-assisted sintering on all the first fine grids on the whole cell piece, and the average contact resistance of the first fine grid after sintering is 2.4 mΩ; then the cell piece is subjected to cutting treatment and passivation treatment, and the average contact resistance of the first fine grid on the split cell piece is 3.0 mΩ; and then the second laser and the second voltage which are the same as the first laser and the first current are used to optimize the contact resistance of the split cell piece, so that the average contact resistance of the first fine grid on the split cell piece can be reduced to 2.5 mΩ.

[0110] According to another specific embodiment of the present application, after forming the first fine grid with a line width of 8.62 μm and a line height of 12.51 μm on the cell sheet, laser-assisted sintering is performed on all the first fine grids on the whole cell sheet by using the first laser and the first voltage, and the average contact resistance of the sintered first fine grids is 2.2 mΩ; then the cell sheet is subjected to cutting treatment and passivation treatment, and the average contact resistance of the first fine grids on the split cell is 3.3 mΩ; and then the split cell is subjected to contact resistance optimization by using the second laser and the second voltage which are the same as the first laser and the first voltage, and the average contact resistance of the first fine grids on the split cell can be reduced to 2.3 mΩ.

[0111] For the fine grid with a narrower line width, the cutting treatment and the passivation treatment have a more obvious effect on the contact resistance of the fine grid. By using the manufacturing method of the solar cell provided in the present embodiment, the first fine grid with excellent contact performance is formed on the cell sheet by laser-assisted sintering, and then the cutting treatment and the passivation treatment are performed, and the contact resistance of the split cell is optimized, so that the contact points of the split cell which are degraded in performance due to the cutting treatment and the passivation treatment can be repaired, and the contact resistance can be reduced again.

[0112] Correspondingly, the present application also provides a solar cell prepared by using the manufacturing method of the solar cell in the above-mentioned embodiments. The same or corresponding parts as the previous embodiments can refer to the corresponding descriptions of the previous embodiments, and will not be described in detail hereinafter.

[0113] The solar cell is prepared by using the manufacturing method in the above-mentioned embodiments, and the first fine grid on the solar cell is sintered by laser-assisted sintering to form a good ohmic contact between the first fine grid and the cell sheet. After the cutting treatment and the passivation treatment, the contact resistance between the first fine grid and the split cell is reduced, but the contact resistance is optimized by using the second laser and the second voltage, and the second laser with a smaller energy density and / or the second voltage with a smaller value can accurately and gently repair the contact resistance to make the metal and the semiconductor re-tightly contact. The good ohmic contact between the fine grid and the split cell in the solar cell is beneficial to reducing the power loss of the solar cell and improving the efficiency of the solar cell.

[0114] The solar cell can be any one of a PERC cell, a PERT cell, a TOPCon cell, and a HJT cell.

[0115] The solar cell can be a single-crystal silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-element compound solar cell. The multi-element compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0116] Figure 5 This is a schematic diagram of a stacked battery provided in an embodiment of this application.

[0117] refer to Figure 5 According to some embodiments of this application, another aspect of this application provides a tandem battery, including: at least two perovskite top cells 201; a crystalline silicon bottom cell 202, the crystalline silicon bottom cell 202 being the solar cell in the above embodiments; and a composite layer 203 located between the perovskite top cell 201 and the crystalline silicon bottom cell 202.

[0118] The perovskite top solar cell 201 may include an electron transport layer 211, a perovskite absorber layer 221 and a hole transport layer 231, with the perovskite absorber layer 221 located between the electron transport layer 211 and the hole transport layer 231.

[0119] The chemical formula of the perovskite absorber layer 221 is ABX3, where A can be CH3NH3. + NH(CH3)2 + Cs + Or Rb + B can be Pb 2+ Sn 2+ Or Sr 2+ X can be I - ,Br - Cl - .

[0120] The materials of electron transport layer 211 include tin oxide, titanium dioxide, and C. 60 Materials such as fullerenes and their derivatives.

[0121] The hole transport layer 231 is made of molybdenum oxide, cuprous thiocyanate, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and poly(3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS).

[0122] exist Figure 5 In one embodiment, the hole transport layer 231 is located between the composite layer 203 and the perovskite absorber layer 221, and the electron transport layer 211 is located on the side of the perovskite absorber layer 221 away from the composite layer 203. In other embodiments, the electron transport layer is located between the composite layer and the perovskite absorber layer, and the hole transport layer is located on the side of the perovskite absorber layer away from the composite layer.

[0123] The composite layer 203 is made of transparent conductive oxide (TCO), metal oxide, or ultrathin metal.

[0124] Transparent conductive oxides include indium tin oxide (ITO) or zinc oxide; metal oxides include MoO. x WOx Or V2O5, etc.; ultrathin metals (1nm~2nm) include gold (Au) or silver (Ag).

[0125] It should be noted that, in Figure 5 In this illustration, the hole transport layer 231 is in direct contact with the composite layer 203, the perovskite absorber layer 221, and the electron transport layer 211, respectively. This does not imply that the perovskite top solar cell 201 only includes the aforementioned film layers. In other embodiments, other film layers may also be included between the hole transport layer 231 and the composite layer 203, between the hole transport layer 231 and the perovskite absorber layer 221, and between the perovskite absorber layer 221 and the electron transport layer 211.

[0126] Figure 6 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application.

[0127] refer to Figure 6 According to some embodiments of this application, another aspect of this application also provides a photovoltaic module, including: a battery component 301, which is a solar cell in the above embodiments or a tandem battery in the above embodiments; a connecting component 302, which is used to connect adjacent battery components 301; an encapsulating film 303, which covers the surface of the battery component 301; and a cover plate 304, which is located on the side of the encapsulating film away from the battery component 301.

[0128] The connecting component 302 includes a busbar and a solder strip. The solder strip is used to connect adjacent solar cells or tandem cells to form a cell string. The solder strip is responsible for transmitting the current generated by the cell string to the busbar. The busbar is used to collect the current from multiple cell strings and transmit it to the junction box to ensure effective current conduction.

[0129] The materials for the 303 film can be organic encapsulation films such as ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyvinyl butyral (PVB) film.

[0130] The cover plate 304 can be a glass cover plate, a plastic cover plate, or other cover plates with light transmission function.

[0131] In some embodiments, the surface of the cover plate 304 facing the adhesive film 303 can be an uneven surface, thereby increasing the utilization rate of incident light.

[0132] exist Figure 6 The positive and negative electrodes of the battery component 301 are located on the two side surfaces of the battery component 301, respectively, and the two ends of the corresponding connecting component 302 are located on the opposite side surfaces of two adjacent battery components 301.

[0133] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be limited by the scope defined by the claims.

Claims

1. A method for manufacturing a solar cell, characterized in that, include: A battery cell is provided, the battery cell including opposing first and second surfaces; A first fine gate is formed on the first surface, and a second fine gate is formed on the second surface; The first surface of the battery cell is irradiated with a first laser, and a first voltage is applied to the first and second fine grids; The battery cell is cut to divide it into at least two battery segments, and the cut surfaces of the battery segments are passivated. The first surface of at least a portion of the segmented cell is irradiated with a second laser, and a second voltage is applied to the first and second fine grids; Wherein, the energy density of the second laser is less than the energy density of the first laser, and / or, the second voltage is less than the first voltage.

2. The method for manufacturing a solar cell according to claim 1, characterized in that, After the passivation treatment is performed, before irradiating at least a portion of the first surface of the sectional cell with the second laser and before applying the second voltage to the first and second grids, the process includes: Obtain the actual contact resistance value of the segmented battery; If the actual contact resistance value is greater than the preset resistance value, the second laser is used to irradiate the first surface of the segmented battery, and the second voltage is applied to the first fine grid and the second fine grid. If the actual contact resistance value is less than or equal to the preset resistance value, then the segmented battery will not be processed.

3. The method for manufacturing a solar cell according to claim 1, characterized in that, After irradiating the first surface of the solar cell with the first laser and applying the first voltage to the first and second grids, and before performing the cutting process, the process includes: performing a first test on the solar cell to obtain a first contact resistance; After the passivation treatment is performed, before irradiating at least a portion of the first surface of the sectional cell with the second laser and before applying the second voltage to the first and second grids, the process includes: A second test is performed on the segmented battery to obtain the second contact resistance; Obtain the deviation value of the second contact resistance compared to the first contact resistance; If the deviation value is greater than the target value, the second laser is used to irradiate the first surface of the segmented battery, and the second voltage is applied to the first fine grid and the second fine grid. If the deviation value is less than or equal to the target value, then the segmented battery will not be processed.

4. The method for manufacturing a solar cell according to claim 3, characterized in that, In the first test, the battery cell is divided into at least two sub-regions, each sub-region corresponding to one of the battery cells, and the first contact resistance is characterized as the contact resistance of the sub-region; In the second test, the second contact resistance is characterized as the contact resistance of the segmented battery.

5. The method for manufacturing a solar cell according to claim 4, characterized in that, In the steps of irradiating the first surface of the segmented cell with the second laser and applying the second voltage to the first and second fine grids, different energy densities of the second laser and the second voltage are selected according to the magnitude of the deviation value.

6. The method for manufacturing a solar cell according to claim 3, characterized in that, In the first test, the battery cell is divided into at least two sub-regions, each sub-region corresponding to one of the battery cells, and the first contact resistance is characterized as the contact resistance between each of the first grids in a certain number of sub-regions and the battery cell. In the second test, the second contact resistance is characterized as the contact resistance between each of the first fine grids selected in the first test and the segmented cell.

7. The method for manufacturing a solar cell according to claim 6, characterized in that, In the step of irradiating the first surface of the cell with the second laser and passing the second voltage to the first and second fine grids, the energy density of the second laser corresponding to different first fine grids is selected according to the magnitude of the deviation value. On the same cell, the magnitude of the second voltage used for different first fine grids is the same.

8. The method for manufacturing a solar cell according to claim 6, characterized in that, In the sub-region, the total number of the first fine gates is a first number, and a second number of the first contact resistances corresponding to the first fine gates are selected in the sub-region, with the ratio of the second number to the first number being 0.5 to 1.

9. The method for manufacturing a solar cell according to claim 1, characterized in that, The second laser is used to irradiate the first surface of all the segmented cells, and the second voltage is applied to the first and second grids.

10. The method for manufacturing a solar cell according to claim 1, characterized in that, The step of irradiating at least a portion of the first surface of the segmented cell with the second laser and applying the second voltage to the first and second grids further includes: irradiating at least a portion of the second surface of the segmented cell with a third laser; wherein the energy density of the third laser is less than the energy density of the second laser.

11. The method for manufacturing a solar cell according to claim 1, characterized in that, The spot size of the first laser is larger than the spot size of the second laser.

12. The method for manufacturing a solar cell according to claim 1, characterized in that, After irradiating at least a portion of the first surface of the segmented cell with the second laser and applying the second voltage to the first and second fine grids, the method further includes: irradiating at least a portion of the second surface of the segmented cell with the second laser and applying the second voltage to the first and second fine grids.

13. A solar cell, characterized in that, It is prepared by the manufacturing method of any one of claims 1 to 12.

14. A stacked battery, characterized in that, include: Perovskite top solar cell; A crystalline silicon bottom cell, wherein the crystalline silicon bottom cell is the solar cell described in claim 13; A composite layer is located between the perovskite top cell and the crystalline silicon bottom cell.

15. A photovoltaic module, characterized in that, include: At least two battery components, wherein the battery components are the solar cells as described in claim 13 or the stacked cells as described in claim 14; A connecting component for connecting adjacent battery components; An adhesive film covering the surface of the battery component; A cover plate located on the side of the adhesive film away from the battery component.

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