Solar fragmented cell and passivation method thereof

Abstract

The invention relates to a solar fragmented cell and a passivation method thereof. The passivation method of the solar fragmented cell is used for carrying out passivation treatment on a cutting surface of a solar fragmented cell green body, and comprises the following steps: providing the solar fragmented cell green body which is provided with the cutting surface; providing a passivation solution, and treating the cutting surface by adopting the passivation solution so as to form a passivation layer on the surface of the cutting surface; and providing laser to irradiate the passivation layer so as to activate the passivation layer and obtain the solar fragmented cell. The solar fragmented cell passivated by the passivation method of the solar fragmented cell has relatively high photoelectric conversion efficiency and relatively good product yield.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cell technology, specifically to a solar cell with slabs and a passivation method thereof. Background Technology

[0002] In the manufacturing process of photovoltaic cells, after silicon wafers are laser-scribed into cells, the cut edges generate numerous dangling bonds, lattice defects, and microcracks. These defects become recombination centers for charge carriers, severely reducing the open-circuit voltage and fill factor of the cell, thus affecting photoelectric conversion efficiency. Currently, the industry commonly uses coating technology to passivate and repair the cut edges of cells to reduce surface recombination rates and improve cell performance. However, traditional passivation processes are ineffective at removing deep defects generated by laser scribing and cannot effectively repair dangling bonds and lattice damage at the cut edges. Therefore, a passivation method is needed to efficiently repair defects and perform multifunctional passivation at the cut edges of cells, thereby improving the photoelectric conversion efficiency and product yield of the cells. Summary of the Invention

[0003] In view of this, this application provides a solar cell with slabs and a passivation method thereof. The solar cell with slabs obtained by passivation using the passivation method of the solar cell with slabs has high photoelectric conversion efficiency and good product yield.

[0004] This application provides a passivation method for solar cell wafers, used to passivate the cut surfaces of a solar cell wafer blank. The passivation method includes: providing a solar cell wafer blank having cut surfaces; providing a passivation liquid and using the passivation liquid to treat the cut surfaces to form a passivation layer on the surface of the cut surfaces; and providing a laser to irradiate the passivation layer to activate the passivation layer and obtain a solar cell wafer.

[0005] Furthermore, the passivation solution includes an in-situ repair agent and a passivating agent. The in-situ repair agent is a silicon-based repair composition, which includes a silane-containing coupling agent and an organosiloxane, wherein the relative molecular mass of the organosiloxane ranges from 300 to 800. The passivating agent is a multifunctional organic passivator, which includes an organic compound containing at least one of a carboxyl group, an amino group, or a sulfonic acid group, wherein the relative molecular mass of the multifunctional organic passivator ranges from 200 to 500.

[0006] Furthermore, the passivation solution satisfies at least one of the following conditions: in the passivation solution, the mass fraction A1 of the in-situ repair agent is in the range of 3% ≤ A1 ≤ 8%; in the passivation solution, the mass fraction A2 of the passivating agent is in the range of 5% ≤ A2 ≤ 12%.

[0007] Furthermore, the passivation solution also includes a conductivity enhancer, wherein the mass fraction A3 of the conductivity enhancer in the passivation solution is in the range of 1% ≤ A3 ≤ 3%.

[0008] Furthermore, the passivation solution also includes a corrosion inhibitor, wherein the mass fraction A4 of the corrosion inhibitor in the passivation solution is in the range of 0.5% ≤ A4 ≤ 2%.

[0009] Furthermore, the passivation solution also includes a solvent, which includes a first solvent and a second solvent, wherein the first solvent is water and the second solvent is at least one of ethanol and isopropanol.

[0010] Furthermore, the provision of the passivation solution and the treatment of the cut surface with the passivation solution to form a passivation layer on the surface of the cut surface include: coating the surface of the cut surface with the passivation solution to form a passivation solution adhesive layer; and heat-treating the passivation solution adhesive layer to obtain the passivation layer.

[0011] Furthermore, the passivation liquid is applied to the surface of the cut surface to form a passivation liquid adhesive layer that satisfies at least one of the following conditions: the coating method includes one of spraying, dipping, or brushing; and the coating time t1 of the cut surface is in the range of 10s≤t1≤60s.

[0012] Further, the passivation liquid adhesive layer is heat-treated to obtain a passivation layer that satisfies at least one of the following conditions: the temperature T for heat treatment of the passivation liquid adhesive layer is in the range of 150℃≤T≤250℃; the heat treatment time t2 for heat treatment of the passivation liquid adhesive layer is in the range of 5min≤t2≤15min; and the thickness d of the passivation layer is in the range of 5μm≤d≤15μm.

[0013] Further, the provision of laser light to irradiate the passivation layer activates the passivation layer to satisfy at least one of the following conditions: the provision of laser light includes providing a laser device to emit laser light, the output power P of the laser device being in the range of 5W ≤ P ≤ 20W; the irradiation time t3 of the passivation layer being in the range of 1s ≤ t3 ≤ 5s; the wavelength of the laser light being 355nm or 532nm; and the scanning speed v of the laser light relative to the solar cell blank being in the range of 50mm / s ≤ v ≤ 150mm / s.

[0014] This application also provides a solar cell segmentation method, which is obtained by passivation treatment of the solar cell segmentation method provided in this application.

[0015] In the passivation method for solar cell slabs provided in this application, the passivation liquid is used to treat the cut surface, forming a uniform and dense passivation layer. This effectively covers and repairs surface defects and saturates dangling bonds on the cut surface, reducing the surface state density and fundamentally suppressing efficiency loss caused by the cut surface. Furthermore, irradiating the passivation layer with a laser further activates the functional groups within it, enhancing the connection stability between the functional groups and the silicon substrate, further reducing the surface recombination rate, and improving the quality of passivation of the solar cell slab blank. The passivation method provided in this application is simple and efficient, requires no vacuum equipment, has low equipment investment costs, and does not require large-scale modifications to existing production lines, significantly reducing the industrialization cost of solar cell slab repair. Furthermore, compared to the solution of directly setting a physical barrier layer on the surface of the cut surface, the solution of this application can accurately penetrate to the microcracks and deep lattice defects generated by laser scribing through the in-situ reaction between the passivation liquid and the cut surface. The in-situ repair components in the passivation liquid form stable chemical bonds with the dangling bonds at the defect sites, achieving dangling bond saturation and lattice damage filling. This fundamentally solves the problem of reduced open circuit voltage and fill factor caused by defects at the cutting edge, and significantly improves the photoelectric conversion efficiency and product yield of solar cell slabs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the implementation will be briefly introduced below. Obviously, the drawings described below are some implementations of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the repair method for solar cell slabs according to the first embodiment of this application; Figure 2 This is a cross-sectional structural diagram of a solar cell slab according to the first embodiment of this application; Figure 3 This is a flowchart illustrating the repair method for solar cell slabs according to the second embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 100 - Solar cell slab, 110 - Cut surface, 120 - Passivation layer, 130 - Silicon substrate. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0021] In this document, references to "embodiment" or "implementation" mean that a particular feature, structure, or characteristic described in connection with an embodiment or implementation may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the manufacturing process of photovoltaic cells, after silicon wafers are laser-scribed into cells, the cut edges generate numerous dangling bonds, lattice defects, and microcracks. These defects become recombination centers for charge carriers, severely reducing the open-circuit voltage and fill factor of the cell, thus affecting photoelectric conversion efficiency. Currently, the industry commonly uses coating technology to passivate and repair the cut edges of cells to reduce surface recombination rates and improve cell performance. However, traditional passivation processes are ineffective at passing through deep defects generated by laser scribing and cannot effectively repair dangling bonds and lattice damage at the cut edges. Furthermore, existing passivation processes still have the following drawbacks: First, they are complex and costly, requiring vacuum equipment and resulting in high equipment investment costs; second, they have limited functionality, primarily focusing on physical passivation, forming a barrier layer on the cut surface, lacking the ability to repair edge defects in situ; third, they have poor compatibility, requiring modifications to existing production lines and increasing the cost of cell repair. Therefore, a passivation method is needed to efficiently repair defects at the cut edges of cells and provide multifunctional passivation to improve the photoelectric conversion efficiency and product yield of the cells.

[0023] Furthermore, vacuum processes such as atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD) are typically used to deposit an inorganic thin film, such as an alumina film or a silicon nitride film, on the cut surface. Field-effect passivation is achieved through the fixed charge of the film. However, this primarily repairs defects on the surface of the cut surface, rather than addressing the defects themselves at the atomic level, resulting in poor repair of deep lattice damage in the silicon substrate. Moreover, existing passivation schemes mainly aim to reduce the surface recombination rate, without systematically addressing the increased contact resistance and susceptibility to corrosion caused by the cut edges. Existing technologies are mostly single methods or simple sequential combinations, with physical stacking of functional layers, lacking synergistic structures formed in situ at the molecular / nanoscale and interwoven with multiple functions, which may lead to interface problems or functional constraints.

[0024] Please see Figure 1 and Figure 2 This application provides a passivation method for a solar cell 100, used to passivate the cut surface 110 of the solar cell blank, the passivation method comprising: S101, providing a solar cell blank with a cut surface 110.

[0025] Understandably, solar cell 100 can be obtained by passivating the cut surface 110 of the solar cell blank.

[0026] Optionally, the solar cell 100 can be, but is not limited to, a two-cell cell, a three-cell cell, or a multi-cell cell.

[0027] Understandably, the cutting surface 110 of the solar cell blank is obtained by laser cutting or mechanical scribing of the whole solar cell.

[0028] Optionally, the solar cell 100 includes a silicon substrate 130, on which a large number of dangling bonds (Si-) exist on the cut surface 110. This means that the silicon atoms on the cut surface 110 have unpaired electrons, and the dangling bonds are highly active defects. This causes photogenerated electrons and holes to recombine and disappear at the surface defects, thus preventing the formation of current. This exacerbates surface recombination and affects the photoelectric conversion efficiency of the solar cell 100.

[0029] S102, a passivation solution is provided, and the passivation solution is used to treat the cut surface 110 to form a passivation layer 120 on the surface of the cut surface 110.

[0030] Understandably, the passivation layer 120 is formed on the surface of the cut surface 110, that is, after the components in the passivation solution form Si-O-Si bonds and coordination bonds with the dangling bonds on the cut surface 110, the passivation solution reacts in situ with the silicon substrate 130 to form a film layer.

[0031] S103, a laser is provided to irradiate the passivation layer 120 to activate the passivation layer 120 and obtain the solar cell 100.

[0032] Understandably, by providing laser to activate the passivation layer 120, precise and controllable activation energy can be provided to the functional groups within the passivation layer 120, enabling the passivation layer 120 to upgrade from a primary film-forming state to a fully functional activated state, further reducing the surface recombination rate and improving the passivation quality of the solar cell blank.

[0033] In the passivation method for the solar cell 100 provided in this embodiment, the passivation liquid is used to treat the cut surface 110, which can form a uniform and dense passivation layer 120 on the cut surface 110. This effectively covers and repairs surface defects and saturates dangling bonds on the cut surface 110, reducing the surface state density of the cut surface 110 and suppressing the efficiency loss caused by the cut surface 110 from the root. Furthermore, irradiating the passivation layer 120 with a laser can further activate the functional groups within the passivation layer 120, thereby strengthening the connection stability between the functional groups within the passivation layer 120 and the silicon substrate, further reducing the surface recombination rate, and improving the quality of passivation of the solar cell blank. The passivation method provided in this application is simple and efficient, requires no vacuum equipment, has low equipment investment costs, and does not require large-scale modification of existing production lines, significantly reducing the industrialization cost of repairing the solar cell 100. Furthermore, compared to the solution of directly setting a physical barrier layer on the surface of the cut surface 110, the solution of this application can accurately penetrate to the microcracks and deep lattice defects generated by laser scribing through the in-situ reaction between the passivation liquid and the cut surface 110. The in-situ repair components in the passivation liquid form stable chemical bonds with the dangling bonds at the defect sites, achieving dangling bond saturation and lattice damage filling. This fundamentally solves the problem of reduced open circuit voltage and fill factor caused by defects at the cutting edge, and significantly improves the photoelectric conversion efficiency and product yield of the solar cell 100.

[0034] Optionally, the solar cell 100 may be of at least one type, including but not limited to PERC cells, TOPCon cells, and HJT cells.

[0035] Optionally, in one specific embodiment, the cutting surface 110 is obtained by laser scribing the entire solar cell. Specifically, the laser wavelength is 1064nm, the power range is 10W to 50W, the scanning speed ranges from 100mm / s to 500mm / s, and the scribing depth ranges from 1 / 3 to 1 / 2 of the thickness of the entire solar cell.

[0036] Optionally, when the solar cell 100 is a multi-cell cell, an asymmetric "grid" four-way path can be used to plan four laser cutting paths, and the cell can be cut into four small pieces of similar area by single or coordinated laser scanning; the cutting path avoids the dense area of ​​the main grid line or the weak edge area of ​​the cell.

[0037] Optionally, the laser parameters for laser scribing the solar cell can be dynamically adjusted according to the thickness of the solar cell.

[0038] Optionally, before cutting the solar cell, non-destructive positioning can be achieved using a vacuum adsorption platform and a vision camera, with a positioning accuracy of ±0.03mm.

[0039] Optionally, the passivation method further includes: before treating the cut surface 110 with the passivation solution, pretreating the cut surface 110 with plasma to remove contaminants from the cut surface 110 and activate the cut surface 110, thereby activating the dangling bonds of the cut surface 110 to facilitate subsequent bonding with functional groups in the passivation solution.

[0040] Specifically, the cut surface 110 is pretreated with ammonia plasma. A preset power is applied to the ammonia gas through a radio frequency power supply to form plasma. The preset power ranges from 100W to 300W, and the processing time ranges from 30s to 120s.

[0041] In some embodiments, the passivation solution includes an in-situ repair agent, which is a silicon-based repair composition. The silicon-based repair composition includes a silane-containing coupling agent and an organosiloxane, wherein the relative molecular mass of the organosiloxane ranges from 300 to 800.

[0042] Understandably, the relative molecular mass of the organosiloxane can be, but is not limited to, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750 and 800.

[0043] Understandably, the in-situ remediation agent is the in-situ remediation component.

[0044] Understandably, one end of the silane-containing coupling agent is an inorganic-loving group that can undergo a hydrolysis reaction with the silicon substrate of the solar cell 100 and form a stable Si-O-Si covalent bond; the other end is an organic-loving group that can undergo a crosslinking reaction with organosiloxanes.

[0045] Understandably, organosiloxanes are a class of polymers or prepolymers with Si-O-Si as the main chain and organic groups (such as methyl, ethyl, and phenyl) attached to the side chains.

[0046] In this embodiment, the in-situ repair agent is a silicon-based repair composition, which includes a silane-containing coupling agent and an organosiloxane. The silane-containing coupling agent forms a connecting bridge between the silicon substrate and the organosiloxane, ensuring the adhesion between the passivation layer 120 and the cut surface 110. The silane-containing coupling agent preferentially adsorbs onto the dangling bond sites of the cut surface 110, forming chemical bonds with the silicon substrate through hydrolysis. Simultaneously, its organic functional groups provide sites for subsequent crosslinking reactions with the organosiloxane, laying the foundation for constructing a continuous Si-O-Si repair network. Furthermore, the Si-O bonds on the molecular chain of the organosiloxane have high bond energy and stable chemical properties, allowing it to directly participate in constructing a dense Si-O-Si bond repair network. It can also crosslink with the organic functional groups of the silane-containing coupling agent to form a three-dimensional network structure, thereby filling the pores of lattice defects. In this embodiment, a silane-containing coupling agent and an organosiloxane are combined. The silane-containing coupling agent acts as an "anchor point," preferentially binding to defect sites in the silicon substrate to solve the problem of weak bonding between the cut surface 110 and the passivation layer 120. The organosiloxane acts as a "network skeleton," cross-linking with the silane-containing coupling agent as nodes to form a rigid covalent network on the surface of the cut surface 110. This gives the passivation layer 120 strong adhesion, density, and stability, ultimately improving the photoelectric conversion efficiency of the solar cell 100.

[0047] Optionally, the silane-containing coupling agent includes, but is not limited to, one or more of aminosilane coupling agents, epoxysilane coupling agents, and methacryloxysilane coupling agents.

[0048] Optionally, the organosiloxane includes, but is not limited to, one or more of methyltrimethoxysilane oligomers, phenyltrimethoxysilane prepolymers, and polydimethylsiloxane (hydroxyl-terminated).

[0049] In some embodiments, the passivation solution further includes a passivating agent, which is a multifunctional organic passivator. The multifunctional organic passivator includes an organic compound containing at least one of a carboxyl group, an amino group, or a sulfonic acid group, and the relative molecular mass of the multifunctional organic passivator ranges from 200 to 500.

[0050] Understandably, the relative molecular mass of the multifunctional organic passivator can be, but is not limited to, 200, 250, 300, 350, 400, 450, 480, and 500.

[0051] Understandably, the multifunctional organic passivator combines with the silicon substrate to form coordination bonds. Specifically, the carboxyl, amino, sulfonic acid and other functional groups in the multifunctional organic passivator have oxygen, nitrogen and sulfur atoms with lone pairs of electrons. The silicon atoms corresponding to the dangling bonds on the silicon substrate surface have empty orbitals. The lone pairs of electrons fill the empty orbitals of the silicon atoms to form coordination bonds.

[0052] In this embodiment, the passivating agent is a multifunctional organic passivating material, which includes organic compounds containing at least one of carboxyl, amino, or sulfonic acid groups. The passivating agent can target the small number of active dangling bonds remaining on the cut surface 110 after in-situ repair. Through the multiple coordination of the multifunctional groups, it further neutralizes the surface active sites of the cut surface 110 to suppress carrier recombination, achieve dangling bond saturation and lattice damage filling, and fundamentally solve the problem of reduced open circuit voltage and fill factor caused by cut edge defects, thereby significantly improving the photoelectric conversion efficiency and product yield of the solar cell 100.

[0053] Understandably, when the relative molecular mass of the multifunctional organic passivator is in the range of 200 to 500, the relative molecular mass of the multifunctional organic passivator is within a reasonable range, so that the diffusion rate of the multifunctional organic passivator is within a reasonable range, allowing it to target the small number of active dangling bonds remaining on the cut surface 110 after in-situ repair, thereby achieving chemical passivation and field-effect passivation of the cut surface 110. When the relative molecular mass of the multifunctional organic passivator is too large, the molecular chain of the multifunctional organic passivator is too long, its diffusion resistance is high, its movement speed is slow, and it is difficult to form a uniform passivation layer 120 on the cut surface 110. When the relative molecular mass of the multifunctional organic passivator is too small, the molecular chain of the multifunctional organic passivator is too short, its migration speed is too fast, resulting in a decrease in the stability of the passivation solution and a poorer passivation effect on the cut surface 110.

[0054] Understandably, in the terminology of this application, "field-effect passivation" refers to the process of creating an "electrostatic field / charge layer" on the cut surface 110 to push charge carriers (electrons or holes) away from the surface of the cut surface 110, preventing them from approaching defects, thereby reducing the effect of surface recombination. The passivating agent forms a negative charge layer on the cut surface 110, generating an electric field effect to repel a small number of charge carriers and reduce surface recombination.

[0055] Understandably, the passivation solution includes the in-situ repair agent and the passivating agent. The in-situ repair agent focuses on repairing lattice defects and building a stable substrate, reducing the surface state density of the cut surface 110, and forming a rigid covalent bond network within the passivation layer 120, thus having the dual function of chemical bonding repair and physical defect filling. The passivating agent focuses on neutralizing residual dangling bonds and suppressing carrier recombination, reducing carrier loss efficiency, and forming single-point or multi-point coordination adsorption structures on the cut surface 110, which is a flexible coordination bonding. Through synergistic effects, the in-situ repair agent and the passivating agent ultimately achieve a dual reduction in the surface state density and surface recombination rate of the cut surface 110, thereby improving the photoelectric conversion efficiency of the solar cell 100.

[0056] In some embodiments, the passivation solution satisfies the following condition: in the passivation solution, the mass fraction A1 of the in-situ repair agent is in the range of 3% ≤ A1 ≤ 8%; Specifically, in the passivation solution, the mass fraction A1 of the in-situ repair agent can be, but is not limited to, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 5%, 5.2%, 5.5%, 6%, 6.5%, 7%, 7.5%, and 8%.

[0057] In the passivation solution provided in this embodiment, when the mass fraction A1 of the in-situ repair agent meets the range of 3% ≤ A1 ≤ 8%, the mass fraction of the in-situ repair agent is within a reasonable range. The repair component of the in-situ repair agent can quickly penetrate into the microcracks and deep lattice defects at the cutting edge. At the same time, the in-situ repair agent can provide sufficient and appropriate reactive sites to carry out efficient dehydration condensation reaction with the dangling bonds on the cutting surface 110, forming a stable Si-O-Si covalent bond network. The passivation layer 120 has strong adhesion, density, and stability, and ultimately improves the photoelectric conversion efficiency of the solar cell 100. When the mass fraction of the in-situ repair agent is too high, it may cause the viscosity of the passivation solution to be too high. The in-situ repair agent may accumulate on the surface of the cutting surface 110 and form an excessively thick and insufficiently dense passivation layer 120, reducing the bonding performance between the passivation layer 120 and the cutting surface 110. Furthermore, excessive in-situ repair agent may cause the silicon-based repair composition to become entangled and aggregated, resulting in the active reaction sites of the in-situ repair agent being encapsulated by itself, failing to fully expose the active groups that bind to the silicon substrate. This significantly reduces the contact probability and reaction efficiency with dangling bonds on the silicon substrate surface, ultimately leading to low repair efficiency for the cut surface 110. When the mass fraction of the in-situ repair agent is too low, the amount of the silicon-based repair composition in the passivation solution is insufficient. Correspondingly, the silane-containing coupling agent is unable to form a connecting bridge between the silicon substrate and the organosiloxane, making it difficult for the organosiloxane to bind dangling bonds and form a covalent bond network on the surface of the cut surface 110. The in-situ repair agent is unable to repair microcracks and deep lattice defects on the cut surface 110, and the reactive sites provided by the in-situ repair agent are insufficient to undergo dehydration condensation reactions with the dangling bonds on the cut surface 110, making it difficult to completely suppress surface recombination.

[0058] In some embodiments, the passivation solution satisfies the following condition: in the passivation solution, the mass fraction A2 of the passivating agent is in the range of 5% ≤ A2 ≤ 12%.

[0059] Specifically, in the passivation solution, the mass fraction A2 of the passivating agent can be, but is not limited to, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 10%, 10.5%, 11%, 11.5%, and 12%.

[0060] In the passivation solution provided in this embodiment, when the mass fraction A2 of the passivating agent meets the range of 5% ≤ A2 ≤ 12%, the mass fraction of the passivating agent is within a reasonable range. The multifunctional organic passivators in the passivating agent have a moderate migration rate and high stability, and can quickly migrate to all defect sites on the cut surface 110, while also providing sufficient adsorption active sites. They fully bond with the dangling bonds on the cut surface 110 to form stable coordination bonds, effectively achieving efficient surface passivation of the cut surface 110. When the mass fraction of the passivating agent is too large, the excessive multifunctional organic passivators in the passivating agent are prone to entanglement, resulting in relatively long molecular chains of the multifunctional organic passivators, slower movement speed, and significantly increased diffusion resistance. They cannot be uniformly dispersed in the passivation solution, and thus it is difficult to fully and uniformly cover the entire cut surface 110. When the mass fraction of the passivating agent is too small, the relative molecular mass of the multifunctional organic passivating material in the passivation solution is too small, and its migration speed is too fast, which leads to a decrease in the stability of the passivation solution. It is difficult for the defect sites and dangling bonds on the cut surface 110 to be stably adsorbed and form effective coordination bonds, ultimately resulting in insufficient passivation layer 120 and inability to effectively reduce the surface recombination rate.

[0061] In some embodiments, the passivation solution further includes a conductivity enhancer, wherein the mass fraction A3 of the conductivity enhancer in the passivation solution is in the range of 1% ≤ A3 ≤ 3%.

[0062] Specifically, in the passivation solution, the mass fraction A3 of the conductive enhancer can be, but is not limited to, 1%, 1.1%, 1.3%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.4%, 2.6%, 2.7%, 2.8%, 2.9%, and 3%.

[0063] Optionally, the conductive enhancer includes at least one of graphene quantum dots and carbon nanotube dispersions.

[0064] Understandably, the film formed by the in-situ repair agent and the passivating agent is dense and has a good passivation effect, but poor conductivity. The conductivity enhancer acts as a conductive bridge, which allows charge carriers to pass smoothly through the passivation layer 120.

[0065] In the passivation solution provided in this embodiment, when the mass fraction A3 of the conductive enhancer meets the range of 1% ≤ A3 ≤ 3%, the mass fraction of the conductive enhancer is within a reasonable range. The conductive enhancer can enhance the conductivity of the passivation solution to form an effective conductive network within the passivation layer 120, thereby reducing the interface resistance and contact resistance of the cut surface 110, preventing the transport of charge carriers in the passivation layer 120 from being blocked, thus reducing the fill factor and ensuring the photoelectric conversion efficiency of the solar cell 100. When the mass fraction of the conductive enhancer is too large, the conductive particles in the conductive enhancer may agglomerate, stack, or aggregate unevenly due to excessive concentration, which may damage the compactness and continuity of the passivation layer 120. At the same time, the conductive enhancer may occupy too many interface sites, interfering with the adsorption of the in-situ repair agent, passivator, and silicon substrate, resulting in insufficient dangling bond repair, reduced chemical passivation and field-effect passivation effects, lower open-circuit voltage, and exacerbating surface recombination. When the mass fraction of the conductive enhancer is too small, it is difficult to form a continuous and interconnected three-dimensional conductive path inside the passivation layer 120, thereby increasing the transport resistance of the charge carriers in the passivation layer 120 and making it difficult to improve the fill factor and photoelectric conversion efficiency of the solar cell 100.

[0066] Optionally, when the conductive enhancer includes the graphene quantum dots, the particle size of the graphene quantum dots ranges from 2 nm to 10 nm.

[0067] In some embodiments, the passivation solution further includes a corrosion inhibitor, wherein the mass fraction A4 of the corrosion inhibitor in the passivation solution is in the range of 0.5% ≤ A4 ≤ 2%.

[0068] Specifically, in the passivation solution, the mass fraction A4 of the corrosion inhibitor can be, but is not limited to, 0.5%, 0.6%, 0.8%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.8%, 1.9%, and 2%.

[0069] In this embodiment, when the mass fraction A4 of the corrosion inhibitor is within the range of 0.5% ≤ A4 ≤ 2%, the mass fraction of the corrosion inhibitor is within a reasonable range. The passivation solution contains a sufficient amount of corrosion-resistant components, which can form a continuous and stable protective film on the surface of the cut surface 110. This effectively blocks external moisture, oxygen, and corrosive media from eroding, preventing the defective areas of the cut surface 110 from being oxidized and corroded, thus avoiding the formation of new recombination centers. This is beneficial to improving the long-term stability of the passivation effect and extending the service life of the solar cell 100. When the mass fraction A4 of the corrosion inhibitor is too high, the excess corrosion inhibitor will accumulate and form crystals, particles, etc., which may damage the integrity of the passivation layer 120. At the same time, it may also cause the structure of the passivation layer 120 to become loose and increase defects, thereby reducing the passivation effect on the cut surface 110, causing a decrease in open-circuit voltage and fill factor, and affecting the photoelectric conversion efficiency of the solar cell 100. When the mass fraction A4 of the corrosion inhibitor is too small, the corrosion-resistant components in the passivation solution are too few, making it difficult to form a dense protective film. This reduces the edge corrosion resistance of the passivation layer 120, making it difficult to effectively block external water vapor, oxygen, and corrosive media from erosion. Consequently, it reduces the long-term stability of the passivation effect and decreases the service life and reliability of the solar cell 100 in outdoor environments.

[0070] Understandably, when the passivation liquid includes the in-situ repair agent, the passivating agent, and the corrosion inhibitor, the corrosion inhibitor has a stronger shrinkage property than the in-situ repair agent and the corrosion inhibitor, thereby enabling the corrosion inhibitor to form a protective structure on the outermost periphery of the passivation layer 120 to improve the edge corrosion resistance of the passivation layer 120.

[0071] Optionally, the corrosion inhibitor includes benzotriazole or a derivative thereof.

[0072] Understandably, the passivation method provided in this application can not only reduce the surface recombination rate, but also systematically solve the problems of increased contact resistance and easy corrosion caused by cutting edges. This application forms a stable passivation layer 120 by combining in-situ repair agents, passivating agents, conductivity enhancers and corrosion inhibitors to form a synergistic structure that is generated in-situ at the molecular / nanoscale and has multiple functions.

[0073] In some embodiments, the passivation solution further includes a solvent, the solvent including a first solvent and a second solvent, the first solvent being water, and the second solvent being at least one of ethanol and isopropanol.

[0074] In this embodiment, the solvent includes a first solvent and a second solvent. The first solvent is water, which provides the necessary hydrolysis environment for the in-situ repair agent, allowing the silane-containing coupling agent in the in-situ repair agent to undergo a hydrolysis reaction and generate reactive silanols, thereby achieving in-situ bonding with the dangling bonds on the cut surface 110. The second solvent has low surface tension and excellent wettability, which can significantly reduce the surface tension of the passivation liquid, allowing the passivation liquid to spread quickly and uniformly on the surface of the cut surface 110, effectively penetrating into the microcracks, grain boundaries, and deep defects of the cut surface 110. This ensures that the in-situ repair agent and the passivation agent can act on the defect sites, improving the passivation effect of the in-situ repair agent and the passivation agent on the cut surface 110. The combination of the first and second solvents in this application facilitates the dissolution and dispersion of each functional component, giving the passivation liquid good stability and good coating performance, making it easier to form the passivation layer 120 on the surface of the cut surface 110.

[0075] Optionally, in some embodiments, the volume ratio of the first solvent to the second solvent is 1 / 3 to 1. Specifically, the volume ratio of the first solvent to the second solvent can be, but is not limited to, 1 / 3, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, and 1.

[0076] In this embodiment, when the volume ratio of the first solvent to the second solvent is within the range of 1 / 3 to 1, and the volume ratio of the first solvent to the second solvent is within a reasonable range (i.e., the volume proportion of water is within a reasonable range), the silane-containing coupling agent in the in-situ repair agent can undergo sufficient hydrolysis to generate enough active groups to fully react and bond with the dangling bonds on the cut surface 110, thus ensuring the passivation effect on the cut surface 110. When the volume ratio of the first solvent to the second solvent is too large (i.e., the volume proportion of water is too large), the stability of the passivation solution may decrease, and the passivation solution may exhibit stratification. Furthermore, it may accelerate the premature hydrolysis of the silane-containing coupling agent in the in-situ repair agent, leading to self-condensation in the aqueous phase and the generation of a large amount of siloxane oligomers, which may prevent the formation of covalent bonds with the dangling bonds on the cut surface 110. When the volume ratio of the first solvent and the second solvent is too small, that is, the volume ratio of water is too small, the hydrolysis reaction of the silane-containing coupling agent in the in-situ repair agent may be too slow, resulting in insufficient hydrolysis products. As a result, the products cannot be fully bonded to the dangling bonds on the cut surface 110, thus reducing the passivation effect on the cut surface 110.

[0077] Optionally, the passivation solution further includes an additive, wherein the mass fraction of the additive in the passivation solution ranges from 0.5% to 2%, and the additive includes at least one of surfactants, pH adjusters, and stabilizers.

[0078] The surfactant includes at least one of polyethylene glycol and sodium dodecylbenzenesulfonate, the pH adjuster includes at least one of ammonia and triethylamine, and the stabilizer includes at least one of polyvinylpyrrolidone and hydroxypropyl methylcellulose.

[0079] Please see Figure 3 In some embodiments, providing a passivation solution and treating the cut surface 110 with the passivation solution to form a passivation layer 120 on the surface of the cut surface 110 includes: S1011, the passivation liquid is applied to the surface of the cut surface 110 to form a passivation liquid adhesive layer.

[0080] S1012, the passivation liquid adhesive layer is heat-treated to obtain the passivation layer 120.

[0081] Optionally, the passivation liquid adhesive layer can be heat-treated by infrared heating or hot air heating.

[0082] In this embodiment, a passivation liquid is applied to the surface of the cut surface 110 to form a passivation liquid adhesive layer, thereby precisely covering the dangling bonds, lattice defects, and microcracks of the cut surface 110. Further, the passivation liquid is heat-treated to provide heat to the in-situ repair agent and passivating agent in the passivation liquid, causing the in-situ repair agent to form a Si-O-Si covalent bond network with the dangling bonds on the surface of the cut surface 110, and the passivating agent to form coordination bonds with the dangling bonds on the cut surface 110. This effectively inhibits surface bonding and simultaneously forms a continuous, dense, and firmly bonded multifunctional integrated film layer, improving the stability of the passivation effect on the solar cell 100.

[0083] Understandably, the passivation method provided in this application employs solution coating and heat treatment processes, eliminating the need for vacuum equipment, operating at low temperatures, being compatible with existing production lines, facilitating large-scale production, and reducing overall production costs by 20% to 30%. Furthermore, the passivation solution uses inexpensive, non-toxic, and harmless raw materials, with no volatile organic compound emissions, thus meeting environmental protection requirements.

[0084] In some embodiments, the application of the passivation liquid to the surface of the cut surface 110 to form a passivation liquid adhesive layer satisfies at least one of the following conditions: The coating method includes one of spraying, dipping, or brushing; it can be understood that the passivation liquid is applied to the surface of the cut surface 110 by one of spraying, dipping, or brushing, so that the passivation liquid is in full contact with the cut surface 110 and bonds with the dangling bonds of the cut surface 110.

[0085] The time t1 for coating the cut surface 110 is in the range of 10s≤t1≤60s.

[0086] Specifically, the value of the coating time t1 for the cut surface 110 can be, but is not limited to, 10s, 15s, 18s, 20s, 25s, 28s, 30s, 35s, 38s, 40s, 45s, 48s, 50s, 52s, 55s, 58s and 60s.

[0087] In this embodiment, when the coating time t1 of the cut surface 110 meets the range of 10s ≤ t1 ≤ 60s, the thickness of the resulting passivation liquid adhesive layer and passivation layer 120 is within a reasonable range. On the one hand, this ensures that the components in the passivation liquid can fully wet the cut surface 110 and form covalent and coordination bonds with the dangling bonds on the surface of the cut surface 110, thus forming a uniform, stable, and functionally complete passivation liquid film layer on the surface of the cut surface 110. On the other hand, this ensures that the thickness of the final passivation layer 120 is within a reasonable range, which can both protect the cut surface 110 and avoid increasing the carrier transport path due to excessive film thickness, ultimately resulting in a high photoelectric conversion efficiency for the solar cell 100. When the coating time on the cut surface 110 is too short, the passivation solution cannot adequately wet the rough structure, microcracks, and lattice defect areas of the cut surface 110, making it difficult to ensure sufficient contact between the in-situ repair agent and passivating agent in the passivation solution and the dangling bonds and defect sites. This results in a poor passivation effect of the passivation solution on the cut surface 110. Simultaneously, the final passivation layer 120 may be too thin, making it prone to damage after a period of use. When the coating time on the cut surface 110 is too long, the passivation solution may locally accumulate on the cut surface 110, resulting in an excessively thick passivation layer 120 with defects such as sagging, shrinkage, pinholes, and cracking, affecting the uniformity of the passivation layer 120. Furthermore, the final passivation layer 120 may be too thick, potentially reducing the carrier transport rate and ultimately affecting the photoelectric conversion efficiency of the solar cell 100.

[0088] In some embodiments, the passivation liquid adhesive layer is heat-treated to obtain the passivation layer 120 that satisfies the condition that the temperature T for heat-treating the passivation liquid adhesive layer is in the range of 150℃≤T≤250℃.

[0089] Specifically, the temperature T for heat treatment of the passivation liquid adhesive layer can be, but is not limited to, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, and 250°C.

[0090] In this embodiment, when the heat treatment temperature T of the passivation liquid adhesive layer meets the range of 150℃≤T≤250℃, the heat treatment temperature is within a reasonable range. This ensures that the solvent is fully extracted from the passivation layer 120 while providing sufficient heat for the in-situ repair agent and the passivating agent. This allows the in-situ repair agent to form covalent bonds with the dangling bonds on the cut surface 110, the passivating agent to form coordination bonds with the dangling bonds on the cut surface 110, and the corrosion inhibitor to form a stable film, ultimately forming a dense and uniform passivation layer 120. Simultaneously, it avoids the decomposition of components in the passivation liquid due to excessively high temperatures, ensuring the passivation performance of the passivation liquid on the cut surface 110. When the heat treatment temperature T of the passivation liquid adhesive layer is too high, the passivating agent and the corrosion inhibitor may undergo thermal decomposition, carbonization, or structural damage, thus failing to perform their functions. Furthermore, excessively high temperatures may cause the passivation layer 120 to shrink excessively, crack, or warp, damaging its integrity and thus reducing the photoelectric conversion efficiency of the solar cell 100. When the temperature T during heat treatment of the passivation solution adhesive layer is too low, it is difficult to provide sufficient heat, resulting in low activity of the components in the passivation solution, making it difficult to bond with the dangling bonds on the cut surface 110, thereby reducing the repair effect on the cut surface 110.

[0091] In some embodiments, the passivation liquid adhesive layer is heat-treated to obtain the passivation layer 120, which satisfies the condition that the heat treatment time t2 of the passivation liquid adhesive layer is in the range of 5min≤t2≤15min; Specifically, the value of the heat treatment time t for the passivation liquid adhesive layer can be, but is not limited to, 5 min, 6 min, 7 min, 7.5 min, 8 min, 8.5 min, 9 min, 10 min, 10.5 min, 11 min, 11.5 min, 12 min, 12.5 min, 13 min, 13.5 min, 14 min, and 15 min.

[0092] In this embodiment, when the heat treatment time t2 of the passivation liquid adhesive layer meets the range of 5min≤t2≤15min, the heat treatment time of the passivation liquid adhesive layer is within a reasonable range. On the one hand, it allows the in-situ repair agent to deeply bond with the dangling bonds on the cut surface 110, effectively repairing lattice defects, filling microcracks, achieving dangling bond saturation, significantly reducing the surface recombination rate, and improving the chemical passivation and in-situ repair effects. On the other hand, it allows the carboxyl, amino, and sulfonic acid groups in the passivation agent to be fully adsorbed, oriented, or coordinated and fixed on the cut surface 110, forming a stable interface charge layer, strengthening field-effect passivation, and effectively improving the open-circuit voltage and fill factor. Furthermore, it can also promote the formation of a through three-dimensional conductive pathway by the conductivity enhancer, allowing the corrosion inhibitor to fully spread and form a protective structure, and ultimately improving the conductivity and corrosion resistance of the passivation layer 120. When the heat treatment time of the passivation liquid adhesive layer is too long, the passivation liquid film layer may experience excessive shrinkage stress, cracking, warping, and detachment due to overheating. Simultaneously, the passivating agent, corrosion inhibitor, and other components may undergo thermal aging and decomposition, reducing the structural integrity and functional stability of the passivation layer 120. Conversely, when the heat treatment time of the passivation liquid adhesive layer is too short, it is difficult to fully and completely evaporate the solvent in the passivation liquid adhesive layer. The residual solvent in the passivation liquid adhesive layer may cause the passivation layer 120 to become loose or form bubbles, resulting in weak interfacial bonding between the passivation layer 120 and the cut surface 110, thus reducing the structural stability and long-term reliability of the passivation layer 120.

[0093] In some embodiments, the passivation liquid adhesive layer is heat-treated to obtain the passivation layer 120 that satisfies the condition that the thickness d of the passivation layer 120 is in the range of 5μm≤d≤15μm.

[0094] Specifically, the thickness d of the passivation layer 120 can be, but is not limited to, 5μm, 5.5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm and 15μm.

[0095] In this embodiment, when the thickness d of the passivation layer 120 satisfies the range of 5μm≤d≤15μm, the thickness of the passivation layer 120 is within a reasonable range. The passivation layer 120 can fully cover the microcracks and lattice defects on the cut surface 110, and perform deep repair and multiple passivation on the cut surface 110. Simultaneously, the passivation layer 120 is not prone to cracking and has good structural stability. When the thickness of the passivation layer 120 is too large, it may lead to an increase in the internal stress of the passivation layer 120, increasing the probability of shrinkage cracking, warping, or detachment, thus compromising the integrity of the passivation layer 120. When the thickness of the passivation layer 120 is too small, it may lead to the exposure of local defects on the cut surface 110 or incomplete repair, increasing the probability of surface recombination and reducing the passivation effect on the cut surface 110.

[0096] In some embodiments, the provision of laser light to irradiate the passivation layer 120 to activate the passivation layer 120 to meet the condition that the provision of laser light includes providing a laser device to emit laser light, wherein the output power P of the laser device is in the range of 5W ≤ P ≤ 20W.

[0097] Specifically, the output power P of the laser device can be, but is not limited to, 5W, 6W, 7W, 8W, 9W, 10W, 11W, 12W, 13W, 14W, 15W, 16W, 17W, 18W, 19W, and 20W.

[0098] In this embodiment, the laser device is used to emit laser light and irradiate the passivation layer 120 to activate the functional groups in the passivation layer 120, thereby promoting the passivation effect of the passivation liquid on the cut surface 110. When the output power P of the laser device meets the range of 5W≤P≤20W, the output power of the laser device is within a reasonable range. This ensures that the laser provides sufficient energy to fully activate the functional groups of the passivation layer 120, enhancing the repair, passivation, conductivity, and corrosion resistance effects. It also avoids excessive laser power leading to ablation of the passivation layer 120, decomposition of organic components, and thermal damage to the silicon substrate, thus ensuring the integrity of the passivation layer 120 and the structural safety of the solar cell 100. When the output power of the laser device is too high, it may cause excessive laser energy density, resulting in localized overheating, ablation, carbonization, cracking, and pinholes in the passivation layer 120, damaging its integrity and density. This may also lead to agglomeration and sintering of the conductive enhancer, damaging the three-dimensional conductive network, increasing the interface resistance, and reducing the fill factor. When the output power of the laser device is too low, the energy density of the laser is too low, which may result in insufficient activation of the passivation layer 120, making it difficult to activate the functional groups in the passivation layer 120 to bond efficiently with the dangling bonds, thus limiting the improvement in the passivation effect.

[0099] In some embodiments, the provision of laser light to irradiate the passivation layer 120 to activate the passivation layer 120 to satisfy the condition that the irradiation time t3 of the passivation layer 120 is in the range of 1s≤t3≤5s.

[0100] Specifically, the value of the irradiation time t3 of the passivation layer 120 can be, but is not limited to, 1s, 1.2s, 1.5s, 1.8s, 2s, 2.2s, 2.3s, 2.5s, 3s, 3.2s, 3.4s, 3.6s, 4s, 4.2s, 4.5s, 4.8s, and 5s.

[0101] In this embodiment, when the irradiation time of the passivation layer 120 meets the range of 1s ≤ t3 ≤ 5s, the irradiation time of the passivation layer 120 is within a reasonable range. This can fully activate the functional groups within the passivation layer 120 to improve the bonding performance of the suspension component, while avoiding damage to the passivation layer 120 due to excessive laser energy. This significantly improves the photoelectric performance and reliability of the solar cell 100. When the irradiation time of the passivation layer 120 is too long, the laser energy may accumulate excessively within the passivation layer 120, causing overheating, ablation, cracking, pinholes, and localized carbonization of the passivation layer 120, ultimately destroying the passivation layer 120. When the irradiation time of the passivation layer 120 is too short, the laser emitted by the laser device is insufficient to fully activate the functional groups in the passivation layer 120, making it difficult for the in-situ repair agent to further condense and form stable Si-O-Si bonds. The passivating agent is difficult to fully arrange and enhance the field effect passivation, and ultimately the passivation effect of the passivation layer 120 is limited.

[0102] In some embodiments, the provision of a laser to irradiate the passivation layer 120 activates the passivation layer 120 to meet the condition that the wavelength of the laser is 355nm or 532nm.

[0103] In this embodiment, when the laser wavelength is 355nm, the laser is ultraviolet light, which can activate the silanol groups in the in-situ repair agent and the polar groups in the corrosion inhibitor to promote further condensation of the Si-O-Si covalent network, making the cross-linking of the passivation layer 120 more compact. When the laser wavelength is 532nm, the laser is green light, which can precisely activate the coordination groups in the passivation agent and the interface of the conductivity enhancer to strengthen the coordination bonding between the passivation agent and the suspension component, the field-effect passivation, and the overlap of the conductive network. The combination of the two laser wavelengths can fully activate the functional groups without damaging the molecular structure of the passivation layer 120, significantly improving the overall effects of passivation, repair, conductivity, and corrosion resistance.

[0104] In some embodiments, the provision of a laser to irradiate the passivation layer 120 to activate the passivation layer 120 to meet the condition that the scanning speed v of the laser relative to the solar cell blank is in the range of 50 mm / s ≤ v ≤ 150 mm / s.

[0105] Specifically, the value of the scanning speed v of the laser relative to the solar cell blank can be, but is not limited to, 50 mm / s, 55 mm / s, 60 mm / s, 65 mm / s, 70 mm / s, 75 mm / s, 80 mm / s, 85 mm / s, 90 mm / s, 95 mm / s, 100 mm / s, 105 mm / s, 110 mm / s, 115 mm / s, 120 mm / s, 125 mm / s, 130 mm / s, 135 mm / s, 140 mm / s, 145 mm / s, and 150 mm / s.

[0106] In this embodiment, when the scanning speed v of the laser relative to the solar cell blank meets the range of 50 mm / s ≤ v ≤ 150 mm / s, the scanning speed of the laser relative to the solar cell blank is within a reasonable range. This ensures that the laser has a reasonable energy residence time on the surface of the passivation layer 120, allowing light energy to be converted into activation energy. This promotes further condensation of the in-situ repair agent, strengthening of the coordination bonds of the passivation agent, effective bonding of the conductivity enhancer, and densification of the corrosion inhibitor, achieving simultaneous activation of multiple functions. This avoids insufficient energy residence, inadequate activation, and limited improvement in passivation and conductivity due to excessively high speed. When the scanning speed of the laser relative to the solar cell blank is too high, the effective residence time of the laser on the surface of the passivation layer 120 is too short, making it difficult to fully activate the functional groups of the passivation layer 120 and improve the repair, passivation, conductivity, and corrosion resistance effects of the passivation layer 120. When the scanning speed of the laser relative to the solar cell blank is too low, the laser may stay in the same area for too long, resulting in excessive local energy accumulation. This can cause the passivation layer 120 to overheat, ablate, carbonize, and form defects such as cracks and pinholes, thereby damaging the structural integrity of the passivation layer 120.

[0107] Optionally, after activating the passivation layer 120, the passivation method further includes cleaning the passivation layer 120 and drying the solar cell 100 to form a dense passivation layer 120.

[0108] The residual passivation solution on the surface of the solar cell 100 can be cleaned using deionized water or organic solvents.

[0109] The temperature range for drying the solar cell 100 is 80°C to 150°C, and the drying time ranges from 5 min to 20 min.

[0110] Please see 1 to Figure 3 This application provides a solar cell 100, which is obtained by passivation treatment using the passivation method provided in this application. After passivation treatment, the solar cell 100 exhibits better performance.

[0111] Understandably, the solar cell 100 of this application is obtained by synergistic treatment with in-situ repair agent and passivating agent, forming a dense passivation layer 120 on the surface of the cut surface 110. Compared with the solution without the passivation liquid treatment, its surface recombination rate is reduced by more than 40%, the open circuit voltage is increased by 15mV to 25mV, the fill factor is increased by 1.5% to 2.5%, the photoelectric conversion efficiency is increased by 0.8% to 1.2%, and the module power is increased by 5W to 8W.

[0112] Understandably, the passivation layer 120 formed by the passivation liquid provided in this application on the cut surface 110 has multiple functions such as chemical passivation, field effect passivation, conductivity enhancement and corrosion protection, which comprehensively improves the performance of the solar cell 100.

[0113] The technical solution of this application will be further described below with reference to several embodiments: Group 1 experiments: Examples 1 to 3, and Comparative Example 1: Example 1: Passivation of PERC solar cells using the passivation method provided in this application.

[0114] (1) Passivation solution formulation: In-situ remediation agent: KH-550 (γ-aminopropyltriethoxysilane) and organosiloxanes (relative molecular mass range of 300 to 800), with a mass fraction A1 of 5%; Passivating agent: Sodium dodecyl sulfate, mass fraction A2 is 8%; Conductivity enhancer: graphene quantum dots, with a mass fraction of A3 of 2%; Corrosion inhibitor: benzotriazole, mass fraction A4 is 1%; The first solvent is water, with a mass fraction of 75%. The second solvent is ethanol and isopropanol, wherein the mass fraction of ethanol is 10% and the mass fraction of isopropanol is 5%. Additive: Ammonia water, used to adjust the pH of the passivation solution to a range of 7 to 8.

[0115] (2) Passivation process parameters: To form the cutting surface 110: laser scribing is used, with a laser wavelength of 1064nm, a power of 30W, a scanning speed of 200mm / s, and a scribing depth of 80μm; Plasma is used to pre-treat the cut surface 110: a preset power is applied to the ammonia gas through a radio frequency power supply to make the ammonia gas form plasma. The preset power is 200W and the treatment time is 60s. The passivation solution is used to treat the cut surface 110: the passivation solution is applied to the surface of the cut surface 110 by spraying, the coating time of the cut surface 110 is 30s, the temperature T of the passivation solution adhesive layer is 200℃, the heat treatment time t2 of the passivation solution adhesive layer is 10min, and the thickness d of the passivation layer 120 is 10μm.

[0116] A laser device emits a laser beam to irradiate the passivation layer 120 in order to activate the passivation layer 120: the output power P of the laser device is 10W, the wavelength of the laser is 355nm, the scanning speed v of the laser relative to the solar cell blank is 100mm / s, and the irradiation time t3 of the passivation layer 120 is 3s. The solar cell 100 is dried at a temperature of 100°C for a time of 10 minutes.

[0117] (3) Test results: Compared to unpassivated solar cell blanks, the solar cell 100 obtained through the above passivation treatment has the following advantages: open circuit voltage increased by 18mV, fill factor increased by 1.8%, photoelectric conversion efficiency increased by 0.9%, module power increased by 5.5W, contact resistance decreased by 15%, corrosion resistance improved, and no corrosion was observed during 48 hours of salt spray testing.

[0118] Example 2: Passivation of TOPCon solar cells using the passivation method provided in this application.

[0119] (1) Passivation solution formulation: In-situ remediation agent: KH-560 (γ-aminopropyltriethoxysilane) and organosiloxanes (relative molecular mass range of 300 to 800), with a mass fraction A1 of 6%; Passivating agent: perfluorosulfonic acid resin, with a mass fraction of A2 of 10%; Conductivity enhancer: carbon nanotube dispersion, mass fraction A3 is 1.5%; Corrosion inhibitor: Methylbenzotriazole, mass fraction A4 is 0.8%; The first solvent is water, with a mass fraction of 70%. The second solvent is ethanol and isopropanol, with ethanol comprising 15% by mass and isopropanol comprising 7% by mass. Additive: Triethylamine, used to adjust the pH of the passivation solution to a range of 7 to 8.

[0120] (2) Passivation process parameters: To form the cutting surface 110: laser scribing is used, with a laser wavelength of 1064nm, a power of 40W, a scanning speed of 150mm / s, and a scribing depth of 100μm; Plasma is used to pre-treat the cut surface 110: a preset power is applied to the ammonia gas through a radio frequency power supply to make the ammonia gas form plasma. The preset power is 250W and the treatment time is 90s. The passivation solution is used to treat the cut surface 110: the passivation solution is applied to the surface of the cut surface 110 by dip coating, the coating time of the cut surface 110 is 20s, the temperature T of the passivation solution adhesive layer is 180℃, the heat treatment time t2 of the passivation solution adhesive layer is 12min, and the thickness d of the passivation layer 120 is 12μm.

[0121] A laser device emits a laser beam to irradiate the passivation layer 120 in order to activate the passivation layer 120: the output power P of the laser device is 15W, the wavelength of the laser is 532nm, the scanning speed v of the laser relative to the solar cell blank is 80mm / s, and the irradiation time t3 of the passivation layer 120 is 4s. The solar cell 100 is dried at a temperature of 120°C for 15 minutes.

[0122] (3) Test results: Compared to unpassivated solar cell blanks, the solar cell 100 obtained through the above passivation treatment has the following advantages: open circuit voltage increased by 22mV, fill factor increased by 2.2%, photoelectric conversion efficiency increased by 1.1%, module power increased by 6.8W, contact resistance decreased by 18%, and corrosion resistance improved, with no corrosion observed during 72 hours of salt spray testing.

[0123] Example 3: Passivation of HJT solar cells was performed using the passivation method provided in this application.

[0124] (1) Passivation solution formulation: In-situ remediation agent: KH-570 (γ-aminopropyltriethoxysilane) and organosiloxanes (relative molecular mass range of 300 to 800), with a mass fraction A1 of 4%; Passivating agent: Sodium dodecylbenzenesulfonate, mass fraction A2 is 7%; Conductivity enhancer: graphene quantum dots, with a mass fraction A3 of 2.5%; Corrosion inhibitor: benzotriazole, mass fraction A4 is 1.2%; The first solvent is water, with a mass fraction of 78%. The second solvent is ethanol and isopropanol, wherein the mass fraction of ethanol is 12% and the mass fraction of isopropanol is 6%. Additive: Triethylamine, used to adjust the pH of the passivation solution to a range of 7 to 8.

[0125] (2) Passivation process parameters: To form the cutting surface 110: laser scribing is used, with a laser wavelength of 1064nm, a power of 25W, a scanning speed of 250mm / s, and a scribing depth of 60μm; Plasma is used to pre-treat the cut surface 110: a preset power is applied to the ammonia gas through a radio frequency power supply to make the ammonia gas form plasma. The preset power is 150W and the treatment time is 120s. The passivation solution is used to treat the cut surface 110: the passivation solution is applied to the surface of the cut surface 110 by brushing, the coating time of the cut surface 110 is 40s, the temperature T of the passivation solution adhesive layer is 220℃, the heat treatment time t2 of the passivation solution adhesive layer is 8min, and the thickness d of the passivation layer 120 is 8μm.

[0126] A laser device emits a laser beam to irradiate the passivation layer 120 in order to activate the passivation layer 120: the output power P of the laser device is 8W, the wavelength of the laser is 355nm, the scanning speed v of the laser relative to the solar cell blank is 120mm / s, and the irradiation time t3 of the passivation layer 120 is 2s. The solar cell 100 is dried at a temperature of 80°C for a time of 20 minutes.

[0127] (3) Test results: Compared to unpassivated solar cell blanks, the solar cell 100 obtained through the above passivation treatment has the following advantages: open circuit voltage increased by 15mV, fill factor increased by 1.5%, photoelectric conversion efficiency increased by 0.7%, module power increased by 4.2W, contact resistance decreased by 12%, corrosion resistance improved, and no corrosion was observed during 48 hours of salt spray testing.

[0128] Comparative Example 1: Passivation of PERC solar cells using a single passivating agent.

[0129] (1) Passivation solution formulation: Passivating agent: Sodium dodecyl sulfate, mass fraction A2 is 15%; The first solvent is water, with a mass fraction of 85%. Additive: Ammonia water, used to adjust the pH of the passivation solution to a range of 7 to 8.

[0130] (2) Passivation process parameters: To form the cutting surface 110: laser scribing is used, with a laser wavelength of 1064nm, a power of 30W, a scanning speed of 200mm / s, and a scribing depth of 80μm; Plasma is used to pre-treat the cut surface 110: a preset power is applied to the ammonia gas through a radio frequency power supply to make the ammonia gas form plasma. The preset power is 200W and the treatment time is 60s. The passivation solution is used to treat the cut surface 110: the passivation solution is applied to the surface of the cut surface 110 by spraying, the coating time of the cut surface 110 is 30s, the temperature T of the passivation solution adhesive layer is 200℃, the heat treatment time t2 of the passivation solution adhesive layer is 10min, and the thickness d of the passivation layer 120 is 10μm.

[0131] A laser device emits a laser beam to irradiate the passivation layer 120 in order to activate the passivation layer 120: the output power P of the laser device is 10W, the wavelength of the laser is 355nm, the scanning speed v of the laser relative to the solar cell blank is 100mm / s, and the irradiation time t3 of the passivation layer 120 is 3s. The solar cell 100 is dried at a temperature of 100°C for a time of 10 minutes.

[0132] (3) Test results: Compared to unpassivated solar cell blanks, the solar cell 100 obtained through the above passivation treatment has the following advantages: open circuit voltage increased by 8mV, fill factor increased by 0.8%, photoelectric conversion efficiency increased by 0.4%, module power increased by 2.5W, contact resistance decreased by 5%, corrosion resistance is average, and slight corrosion was observed during 24 hours of salt spray testing.

[0133] As can be seen from the data of Examples 1 to 3 and Comparative Example 1, the passivation method provided in this application is applicable to passivating various types of solar cell 100, such as PERC cells, TOPCon cells, and HJT cells. Compared with unpassivated solar cell blanks, the passivation method provided in this application can effectively improve the open-circuit voltage, fill factor, photoelectric conversion efficiency, module power, and corrosion resistance of the solar cell 100, while reducing contact resistance, thus giving the solar cell 100 better performance. Furthermore, by comparing Example 1 and Comparative Example 1, if the passivation liquid uses a single passivating agent, its passivation effect on the cut surface 110 is significantly lower than that of the passivation liquid provided in this application. This indicates that the in-situ repair agent, passivating agent, conductivity enhancer, and corrosion inhibitor in the passivation liquid provided in this application have significant synergistic passivation performance.

[0134] Second group of experiments: Comparative Example 2 and Example 1: Comparative Example 2: A silicon nitride thin film was deposited on the surface of the cut surface 110 using PECVD. The reaction gases were SiH4 and NH3, the reaction temperature was 300℃, the deposition time was 180s, and the thickness of the silicon nitride thin film was 80nm.

[0135] Compared to unpassivated solar cell blanks, the solar cell 100 obtained through the above deposition treatment has the following advantages: open circuit voltage increased by 12mV, fill factor increased by 1.2%, photoelectric conversion efficiency increased by 0.6%, module power increased by 3.5W, contact resistance decreased by 8%, corrosion resistance is average, and slight corrosion was observed during 24 hours of salt spray testing.

[0136] As can be seen from the data of Example 1 and Comparative Example 2, the performance parameters of the solar cell 100 obtained by the passivation method provided in this application are better than those of the solar cell 100 obtained by directly depositing a silicon nitride thin film on the surface of the cut surface 110. In addition, the passivation method of this application has advantages such as lower production cost and lower equipment investment cost compared with the method of Comparative Example 2.

[0137] Third group of experiments: Examples 4 to 6: Under the same conditions, the different ratios of the passivation solution were optimized.

[0138] Table 1 below shows the composition parameters of the passivation solution used in the passivation process of the solar cell 100 in Examples 4 to 6. Table 1: Composition parameters of the passivation solution during the passivation process of the solar cell 100 in Examples 4 to 6

[0139] The solar cell 100 obtained by passivation with the above passivation solution has optimized performance parameters compared with the solar cell blank without passivation treatment. Table 2 below shows the performance parameters of the solar cell 100 in Examples 4 to 6. Table 2: Performance parameters of solar cell 100 in Examples 4 to 6

[0140] Please refer to Tables 1 and 2. As can be seen from the data of Examples 4 to 6, the solar cell 100 obtained in Example 5 achieves the best balance in terms of performance, cost and process stability. The ratio of its passivation solution is the preferred ratio. Specifically, the mass fraction of the in-situ repair agent is 5%, the mass fraction of the passivation agent is 8%, the mass fraction of the conductive enhancer is 2%, and the mass fraction of the corrosion inhibitor is 1%.

[0141] In this application, the terms "embodiment" and "implementation" mean that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of these phrases in various locations throughout the specification does not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this application can be combined with other embodiments. Furthermore, it should be understood that the features, structures, or characteristics described in the various embodiments of this application can be arbitrarily combined to form another embodiment that does not depart from the spirit and scope of the technical solution of this application, provided there is no contradiction between them.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A passivation method for solar cell wafers, used to passivate the cut surfaces of a solar cell wafer blank, characterized in that, The passivation method includes: A solar cell preform is provided, the solar cell preform having a cut surface; A passivation solution is provided, and the cut surface is treated with the passivation solution to form a passivation layer on the surface of the cut surface; and A laser is provided to irradiate the passivation layer to activate it and obtain a solar cell.

2. The passivation method according to claim 1, characterized in that, The passivation solution includes an in-situ repair agent and a passivating agent. The in-situ repair agent is a silicon-based repair composition, which includes a silane-containing coupling agent and an organosiloxane, wherein the relative molecular mass of the organosiloxane ranges from 300 to 800. The passivating agent is a multifunctional organic passivator, which includes an organic compound containing at least one of a carboxyl group, an amino group, or a sulfonic acid group, wherein the relative molecular mass of the multifunctional organic passivator ranges from 200 to 500.

3. The passivation method according to claim 2, characterized in that, The passivation solution satisfies at least one of the following conditions: In the passivation solution, the mass fraction A1 of the in-situ repair agent ranges from 3% to 8%. In the passivation solution, the mass fraction A2 of the passivating agent is in the range of 5% ≤ A2 ≤ 12%.

4. The passivation method according to claim 2, characterized in that, The passivation solution also includes a conductivity enhancer, and the mass fraction A3 of the conductivity enhancer in the passivation solution is in the range of 1% ≤ A3 ≤ 3%.

5. The passivation method according to claim 2, characterized in that, The passivation solution also includes a corrosion inhibitor, wherein the mass fraction A4 of the corrosion inhibitor in the passivation solution is in the range of 0.5% ≤ A4 ≤ 2%.

6. The passivation method according to claim 2, characterized in that, The passivation solution further includes a solvent, which includes a first solvent and a second solvent. The first solvent is water, and the second solvent is at least one of ethanol and isopropanol.

7. The passivation method according to claim 1, characterized in that, The provision of the passivation solution, and the treatment of the cut surface with the passivation solution to form a passivation layer on the surface of the cut surface, includes: The passivation liquid is applied to the surface of the cut surface to form a passivation liquid adhesive layer; and The passivation liquid adhesive layer is subjected to heat treatment to obtain the passivation layer.

8. The passivation method according to claim 7, characterized in that, The passivation liquid is applied to the surface of the cut surface to form a passivation liquid adhesive layer that satisfies at least one of the following conditions: The coating method includes one of spraying, dipping, or brushing; The time t1 for coating the cut surface is in the range of 10s≤t1≤60s.

9. The passivation method according to claim 7, characterized in that, The passivation liquid adhesive layer is subjected to heat treatment to obtain a passivation layer that satisfies at least one of the following conditions: The temperature range T for heat treatment of the passivation liquid adhesive layer is: 150℃≤T≤250℃; The heat treatment time t2 for the passivation liquid adhesive layer is in the range of 5 min ≤ t2 ≤ 15 min; The thickness d of the passivation layer is in the range of 5μm≤d≤15μm.

10. The passivation method according to claim 1, characterized in that, The laser is provided to irradiate the passivation layer to activate the passivation layer to satisfy at least one of the following conditions: The provision of laser includes providing a laser device to emit laser light, wherein the output power P of the laser device is in the range of 5W ≤ P ≤ 20W; The irradiation time t3 of the passivation layer is in the range of 1s ≤ t3 ≤ 5s; The wavelength of the laser is 355nm or 532nm; The scanning speed v of the laser relative to the solar cell blank is in the range of 50 mm / s ≤ v ≤ 150 mm / s.

11. A solar cell with segmented cells, characterized in that, The solar cell is obtained by passivation treatment using the passivation method for solar cells according to any one of claims 1 to 10.

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