Insulating adhesive for solar cell string and solar cell string

Abstract

The application discloses a kind of solar cell string insulating glue and solar cell string, the mass percentage of multifunctional acrylic resin in solar cell string insulating glue is between 50% and 85%;The mass percentage of epoxy resin in solar cell string insulating glue is between 1% and 5%;The mass percentage of active toughening agent in solar cell string insulating glue is between 1% and 10%;The mass percentage of coupling agent in solar cell string insulating glue is between 1% and 10%;The mass percentage of softening agent in solar cell string insulating glue is between 1% and 10%;The mass percentage of auxiliary agent in solar cell string insulating glue is between 0.2% and 1%;The mass percentage of photoinitiator in solar cell string insulating glue is between 0.5% and 1%;The mass percentage of dispersing agent in solar cell string insulating glue is between 0.1% and 0.5%.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and more particularly to an insulating adhesive for solar cell strings and a solar cell string. Background Technology

[0002] BC batteries (back-contact crystalline silicon photovoltaic cells) have a unique structure where both positive and negative electrodes are integrated on the back side. This makes the circuit connections, insulation protection, and thermal expansion adaptation designs between the corresponding series-connected cell strings more complex. During the encapsulation process of the series-connected cell strings for BC batteries, in order to ensure the long-term electrical safety of adjacent solar cell strings and avoid risks such as inter-string leakage and inter-string arcing, existing BC batteries must reserve a relatively wide physical spacing between strings, also known as inter-string distance. This excessively large inter-string distance has become a core bottleneck restricting the performance upgrade and application expansion of BC batteries, directly leading to prominent problems such as limited efficiency improvement and insufficient aesthetics.

[0003] Currently, the main methods for reducing inter-serial distance include using high CTI (Comparative Tracking Index) encapsulation, shingled / multi-segment technology, and smart junction boxes. However, high CTI encapsulation is 30% to 50% more expensive than conventional encapsulation, shingled / multi-segment technology requires high equipment precision, and smart junction boxes are also expensive, making them unsuitable for conventional manufacturing processes. Summary of the Invention

[0004] This invention provides an insulating adhesive for solar cell strings and a solar cell string. The insulating adhesive has the characteristics of transparency, high insulation rate, high resistivity and high buffering performance. Using this insulating adhesive can effectively reduce the inter-string distance between solar cell strings and protect the solar cell silicon wafer from damage caused by lamination and encapsulation pressure and outdoor stress, thus playing the dual role of an insulating adhesive material.

[0005] In a first aspect, embodiments of the present invention provide an insulating adhesive for solar cell strings, comprising:

[0006] The multifunctional acrylic resin accounts for 50% to 85% of the mass percentage in the insulating adhesive for the solar cell string.

[0007] The epoxy resin accounts for 1% to 5% of the mass percentage in the insulating adhesive for the solar cell string.

[0008] The active toughening agent is present in the insulating adhesive for the solar cell string at a mass percentage between 1% and 10%.

[0009] The coupling agent is present in the insulating adhesive for the solar cell string at a mass percentage between 1% and 10%.

[0010] The softener is present in the insulating adhesive for the solar cell strings at a mass percentage between 1% and 10%.

[0011] The additives constitute 0.2% to 1% by mass in the insulating adhesive for the solar cell strings.

[0012] The photoinitiator accounts for 0.5% to 1% by mass in the insulating adhesive used in the solar cell string.

[0013] The dispersant is present in the insulating adhesive for the solar cell strings at a mass percentage between 0.1% and 0.5%.

[0014] The pigment, by mass percentage, is between 0% and 10% in the insulating adhesive used for the solar cell strings;

[0015] The ultraviolet light absorber accounts for 0% to 2% of the mass percentage in the insulating adhesive used in the solar cell string.

[0016] Optionally, the multifunctional acrylic resin includes at least one of tricyclodecanediethanol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, bis(trimethylolpropane)tetraacrylate, dipolypentaerythritol polyacrylate, and epoxidized dipolypentaerythritol polyacrylate.

[0017] Optionally, the epoxy resin includes at least one of bisphenol A type epoxy resin and alicyclic epoxy resin.

[0018] Optionally, the coupling agent includes at least one of silane coupling agents, silane oligomers, and titanate coupling agents.

[0019] Optionally, the additives include leveling agents and defoamers; wherein,

[0020] The leveling agent is present in the insulating adhesive for solar cell strings at a mass percentage between 0.1% and 0.5%.

[0021] The defoamer is present in the insulating adhesive for solar cell strings at a mass percentage between 0.1% and 0.5%.

[0022] Optionally, the leveling agent includes at least one of silicone-modified polyether leveling agents and silicone leveling agents;

[0023] And / or, the defoamer includes at least one of polyether defoamers and silicone defoamers.

[0024] Optionally, the photoinitiator includes at least one of benzoyl peroxide, dicumyl peroxide, tert-butyl peroxide, and tert-butyl percarbonate-2-ethylhexyl.

[0025] Optionally, the pigment includes at least one of titanium dioxide, barium sulfate, cadmium red, iron oxide red, scarlet powder, carbon black, copper chromium black, iron chromium black, cobalt chromium blue, phthalocyanine blue, malachite green, and phthalocyanine green.

[0026] Optionally, the ultraviolet absorber includes at least one of triazine-type ultraviolet absorbers and benzophenone-type ultraviolet absorbers.

[0027] Secondly, embodiments of the present invention also provide a solar cell string, including an insulating member, said insulating member being made of insulating adhesive for solar cell strings as described in any one of the first aspects.

[0028] This invention provides an insulating adhesive for solar cell strings and a solar cell string itself. The insulating adhesive for solar cell strings comprises a multifunctional acrylic resin, an epoxy resin, an active toughening agent, a coupling agent, a softener, additives, a photoinitiator, a dispersant, a pigment, and an ultraviolet absorber. The multifunctional acrylic resin constitutes 50% to 85% of the mass of the insulating adhesive for solar cell strings; the epoxy resin constitutes 1% to 5% of the mass of the insulating adhesive for solar cell strings; the active toughening agent constitutes 1% to 10% of the mass of the insulating adhesive for solar cell strings; and the coupling agent constitutes a significant portion of the mass of the insulating adhesive for solar cell strings. The mass percentage of the adhesive in the solar cell string insulating adhesive is between 1% and 10%; the mass percentage of the softener in the solar cell string insulating adhesive is between 1% and 10%; the mass percentage of the additives in the solar cell string insulating adhesive is between 0.2% and 1%; the mass percentage of the photoinitiator in the solar cell string insulating adhesive is between 0.5% and 1%; the mass percentage of the dispersant in the solar cell string insulating adhesive is between 0.1% and 0.5%; the mass percentage of the pigment in the solar cell string insulating adhesive is between 0% and 10%; and the mass percentage of the ultraviolet light absorber in the solar cell string insulating adhesive is between 0% and 2%. This invention employs a high resistivity (e.g., resistivity per unit volume > 10) material. 14This insulating adhesive, with its high resistivity (Ω•cm) properties, possesses superior insulation properties due to its inherent high resistivity. This results in ultra-high insulation, strong adhesion, and ultra-thin coating capabilities (e.g., coating thickness <0.1mm), providing a technological basis for reducing inter-string distances. Specifically, this insulating adhesive exhibits characteristics such as transparency, high insulation rate, high resistivity, and high buffering performance. Using this adhesive can effectively reduce the inter-string distance between solar cell strings and protect the solar cell silicon wafers from damage caused by lamination and encapsulation pressure and outdoor stress, thus serving a dual purpose as an insulating adhesive.

[0029] Furthermore, it is detailed that the insulating adhesive has an insulation strength greater than 2000V / mm, and thus can withstand a voltage of 200V with a coating thickness of 0.1mm, far exceeding the operating voltage of a single cell (approximately 0.6V), completely eliminating the risk of short circuits caused by reducing the inter-cell spacing; the ultra-thin insulating film layer formed by the cured insulating adhesive has a resistivity per unit volume greater than 10 Ω·cm, which blocks leakage current paths. 14 The leakage current is reduced by more than 90% (Ω•cm, compared to an air gap, or in contrast to a solution where the solar cell strings are not coated with this insulating adhesive, in which case the solar cell strings are spaced apart and air is present in the gaps between them), thereby improving the insulation reliability between multiple solar cell strings. Furthermore, the inter-string distance between solar cell strings can be reduced to below 0.3mm, increasing the effective light-receiving area of ​​the solar cells from 80% to 95%. This allows for accommodating 5%–8% more solar cells within the same module area, and also reduces reflection losses of incident light at the gaps between solar cell strings. The overall light absorption rate of multiple solar cell strings is increased by 3%–5%, and the overall power density of multiple solar cell strings is increased by 8%–12%. The reduction in inter-string distance also correspondingly shortens the heat conduction path, lowers the operating temperature, reduces efficiency degradation, saves manufacturing costs and materials, improves production efficiency, and reduces transportation and power costs. Furthermore, the insulating adhesive can be bonded to the two opposite ends of the solar cell string in the series direction. The solar cell string bonded with the insulating adhesive forms an integral structure. Under pressure, the insulating adhesive plays a stress buffering role, improving bending strength and reducing the incidence of microcracks.

[0030] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a top view schematic diagram of the coating relationship between an insulating adhesive for a solar cell string and the corresponding solar cell string, provided in an embodiment of the present invention.

[0033] Figure 2 This is a side view schematic diagram of the coating relationship between an insulating adhesive for a solar cell string and the corresponding solar cell string, provided in an embodiment of the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0036] BC cells are currently the most efficient crystalline silicon solar cells in terms of photoelectric conversion. Structurally, the positive and negative electrodes of a BC cell are concentrated on the back of the cell, for example, they can be arranged alternately. Furthermore, the fact that both electrodes are located on the back means the front of the cell is fully exposed to sunlight, improving the absorption efficiency. Multiple BC cells are connected in series to form a solar cell string. To ensure the long-term electrical safety of adjacent solar cell strings and avoid risks such as inter-string leakage and arcing, a relatively wide physical gap must be maintained between adjacent solar cell strings, which can be understood as the inter-string distance. However, on the one hand, the gap area corresponding to this inter-string distance cannot participate in the absorption and photoelectric conversion of solar radiation, which is equivalent to indirectly compressing the effective light-receiving area of ​​the corresponding solar cell string. For the same size, compared to conventional solar cell strings without significant inter-string distance, the photoelectric conversion efficiency of BC cells will decrease by 1% to 3%, especially under high light intensity conditions, where the loss of photoelectric conversion efficiency is more pronounced. On the other hand, a wider inter-string spacing increases the circuit transmission path between adjacent solar cell strings, leading to increased series resistance, additional Joule losses, and further weakening the overall photoelectric conversion efficiency of adjacent solar cell strings. Furthermore, besides the photoelectric conversion efficiency issue, excessive inter-string spacing also severely affects the aesthetics of BC cells and their corresponding solar cell strings. This spacing creates wide gaps between adjacent solar cell strings, forming clearly visible dividing bands on the overall surface of the strings, disrupting the integrity and consistency of the light-receiving surface and giving the overall surface of adjacent solar cell strings a distinct segmented appearance. This lack of aesthetic appeal greatly limits the widespread application of BC cells in scenarios with high aesthetic requirements, hindering the further expansion of their market coverage.

[0037] To address the aforementioned technical problems, this invention provides an insulating adhesive for solar cell strings. This insulating adhesive for solar cell strings comprises a multifunctional acrylic resin, an epoxy resin, an active toughening agent, a coupling agent, a softener, additives, a photoinitiator, a dispersant, a pigment, and an ultraviolet absorber. The multifunctional acrylic resin constitutes 50% to 85% of the total mass of the insulating adhesive for solar cell strings; the epoxy resin constitutes 1% to 5% of the total mass of the insulating adhesive for solar cell strings; the active toughening agent constitutes 1% to 10% of the total mass of the insulating adhesive for solar cell strings; and the coupling agent constitutes 1% to 10% of the total mass of the insulating adhesive for solar cell strings. The percentage of softener in the insulating adhesive for solar cell strings is between 1% and 10% by mass; the percentage of additives in the insulating adhesive for solar cell strings is between 0.2% and 1% by mass; the percentage of photoinitiator in the insulating adhesive for solar cell strings is between 0.5% and 1% by mass; the percentage of dispersant in the insulating adhesive for solar cell strings is between 0.1% and 0.5% by mass; the percentage of pigment in the insulating adhesive for solar cell strings is between 0% and 10% by mass; and the percentage of ultraviolet absorber in the insulating adhesive for solar cell strings is between 0% and 2% by mass.

[0038] Specifically, the formulation of the insulating adhesive for this solar cell string is designed to balance insulation reliability, weather resistance, mechanical compatibility, and process adaptability. The components achieve a synergistic effect through precise proportions, and the percentage range of each component is precisely optimized. This avoids performance defects caused by excessive amounts of a single component while ensuring the full functionality of each component. The functions of each component and their percentage ranges are explained in detail below.

[0039] Multifunctional acrylic resin, as the base film-forming resin of the insulating adhesive for solar cell strings, is the main component that determines the basic mechanical properties, insulation properties, curing rate, and adhesion to the solar cell strings. For example, the multifunctional (e.g., trifunctional, hexafunctional) structure of the multifunctional acrylic resin can be rapidly cross-linked by ultraviolet light, forming a dense three-dimensional network structure, ensuring the density and stability of the insulating film layer formed by the cured adhesive. A proportion range of 50% to 85% ensures the formation of a continuous and complete insulating film layer. If the mass percentage of multifunctional acrylic resin in the insulating adhesive for solar cell strings is less than 50%, a continuous insulating film layer cannot be formed, the insulation performance drops sharply, and leakage risk in the solar cell strings is easily triggered. If the mass percentage of multifunctional acrylic resin in the insulating adhesive for solar cell strings is higher than 85%, other components are less effective, the adhesive is prone to cracking after curing, and the weather resistance and stability of the solar cell strings are affected.

[0040] Epoxy resin, used as an auxiliary film-forming resin in the insulating adhesive for solar cell strings, forms an interpenetrating network structure with multifunctional acrylic resin, which can improve the high-temperature resistance, chemical corrosion resistance, and adhesion of the insulating adhesive for solar cell strings. For example, the epoxy groups of the epoxy resin can chemically react with the hydroxyl and carboxyl groups of the acrylic resin to further densify the cross-linked network and enhance the structural stability of the insulating film layer formed by the cured adhesive. A percentage of 1% to 5% can improve the high-temperature resistance of the insulating film layer, enabling it to withstand the lamination temperature during the solar cell string encapsulation process. If the mass percentage of epoxy resin in the insulating adhesive for solar cell strings is less than 1%, the improvement in high-temperature resistance is not significant, and deformation of the insulating film layer is likely to occur during lamination. If the mass percentage of epoxy resin in the insulating adhesive for solar cell strings is greater than 5%, the cured adhesive will become more brittle, and its compatibility with the acrylic resin will decrease, potentially leading to phase separation and reducing the uniformity of the insulating film layer.

[0041] Active toughening agents improve the toughness and impact resistance of the insulating film formed by the cured insulating adhesive, alleviate internal stress during the curing process, and prevent cracking of the insulating film caused by temperature changes (such as diurnal temperature differences and high-low temperature cycling). Active toughening agents contain reactive functional groups that participate in the resin crosslinking reaction and are uniformly dispersed in the crosslinking network. A percentage of 1% to 10% can significantly improve the elongation at break of the insulating film and enhance its impact resistance. If the mass percentage of active toughening agent in the insulating adhesive for solar cell strings is less than 1%, the toughening effect is not significant, and the insulating film is prone to cracking due to internal stress. If the mass percentage of active toughening agent in the insulating adhesive for solar cell strings is greater than 10%, it will dilute the crosslinking density, leading to a decrease in insulation resistance and potentially reducing the curing rate of the insulating adhesive.

[0042] Coupling agents enhance the interfacial adhesion between the insulating film layer formed by the cured insulating adhesive and the surface of the solar cell string, improving interfacial compatibility and preventing insulation failure due to interfacial peeling during long-term use. A concentration of 1% to 10% can effectively cover the substrate surface, forming a stable interfacial bonding layer, improving adhesion strength, and preventing interfacial peeling of the insulating film layer in humid and hot environments. If the mass percentage of the coupling agent in the insulating adhesive for solar cell strings is less than 1%, the interfacial adhesion is insufficient, and the insulating film layer is prone to detachment. If the mass percentage of the coupling agent in the insulating adhesive for solar cell strings is greater than 10%, the coupling agent will accumulate excessively at the interface, leading to gaps between the insulating film layer and the surface of the solar cell string, reducing insulation performance and mechanical stability.

[0043] The softener can lower the curing temperature of the insulating film layer formed by the insulating adhesive, improve low-temperature flexibility, and prevent the solar cell string from cracking due to embrittlement of the insulating film layer in low-temperature environments. It can also adjust the application viscosity of the insulating adhesive, improving coating uniformity. A percentage of 1% to 10% can improve low-temperature toughness. If the softener's mass percentage in the insulating adhesive for solar cell strings is less than 1%, the low-temperature toughness is insufficient, and the insulating film layer of the solar cell string is prone to cracking in cold regions. If the softener's mass percentage in the insulating adhesive for solar cell strings is greater than 10%, it will lead to a decrease in the hardness and tensile strength of the insulating film layer, making it prone to deformation during long-term use and potentially affecting insulation performance.

[0044] Additives may include, but are not limited to, defoamers, leveling agents, and antioxidants, which can improve the workability and storage stability of the insulating adhesive. For example, defoamers can eliminate bubbles generated during the coating process, preventing pinholes in the insulating film layer formed by the cured adhesive. For example, leveling agents can improve the surface smoothness of the insulating film layer formed by the cured adhesive, ensuring uniform insulation. For example, antioxidants can delay resin aging and extend the service life of the insulating adhesive. A percentage range of 0.2% to 1% can effectively perform auxiliary functions; for example, defoamers can quickly eliminate bubbles during the coating process, and leveling agents can improve the surface roughness of the insulating film layer. If the mass percentage of additives in the insulating adhesive for solar cell strings is less than 0.2%, construction defects such as bubbles and sagging are likely to occur. If the mass percentage of additives in the insulating adhesive for solar cell strings is greater than 1%, it will affect the compatibility and cross-linking reaction of the resin system, reducing the mechanical properties and stability of the insulating film layer.

[0045] Photoinitiators decompose under ultraviolet light to generate free radicals, initiating cross-linking polymerization of multifunctional acrylic resins and determining the curing rate and degree of curing of the adhesive. A percentage range of 0.5% to 1% ensures sufficient free radical concentration, allowing the adhesive to cure rapidly under ultraviolet light. If the mass percentage of photoinitiator in the insulating adhesive for solar cell strings is less than 0.5%, the curing rate will be too slow, affecting production efficiency, and incomplete curing will reduce the performance of the insulating film. If the mass percentage of photoinitiator in the insulating adhesive for solar cell strings is greater than 1%, the curing shrinkage rate will be too large, easily leading to cracking of the insulating film layer, and residual photoinitiator will reduce the weather resistance of the insulating adhesive.

[0046] Dispersants improve the uniformity of dispersion of various solid components in the resin system, prevent particle agglomeration, and ensure the consistency of the performance of the insulating film layer formed by the cured insulating adhesive. Dispersants can adsorb onto the surface of solid particles, reducing the attraction between particles and forming a stable dispersion system. A proportion range of 0.1% to 0.5% can effectively prevent solid particle agglomeration, ensuring a dispersed particle size ≤1μm, guaranteeing the insulation uniformity and surface smoothness of the insulating film layer. If the mass percentage of dispersant in the insulating adhesive for solar cell strings is less than 0.1%, solid particles are prone to agglomeration, forming insulation defects. If the mass percentage of dispersant in the insulating adhesive for solar cell strings is greater than 0.5%, it will lead to abnormal adhesive viscosity, affecting the coating process and potentially reducing the mechanical properties of the insulating film layer.

[0047] Pigments primarily function for coloring and can be added as needed (e.g., black pigment for shading to prevent light interference between solar cells). They also enhance the UV aging resistance of the insulating film formed by the cured adhesive. Commonly used pigments are inorganic (such as carbon black and titanium dioxide), which possess good weather resistance and stability. A pigment content of 0%–10% achieves uniform coloring without affecting the crosslinking density and insulation performance of the resin system. If the pigment percentage in the insulating adhesive for solar cell strings exceeds 10%, pigment particles are prone to agglomeration, leading to defects in the insulating film and increasing adhesive viscosity, thus affecting application performance.

[0048] Ultraviolet (UV) absorbers can absorb UV light from sunlight, delaying the aging and degradation of the resin system, improving the weather resistance of the insulating adhesive, and extending the lifespan of solar cell strings using this adhesive. A concentration of 0% to 2% effectively absorbs UV light and reduces the rate of photo-oxidative degradation of the resin. However, if the mass percentage of the UV absorber in the insulating adhesive for solar cell strings exceeds 2%, it will cause the UV absorber to precipitate on the surface of the insulating film, forming a white powder that affects appearance and adhesion.

[0049] The technical solution in this embodiment of the invention employs a high resistivity (e.g., resistivity per unit volume > 10). 14 This insulating adhesive, with its high resistivity (Ω•cm) properties, possesses superior insulation properties due to its inherent high resistivity. This results in ultra-high insulation, strong adhesion, and ultra-thin coating capabilities (e.g., coating thickness <0.1mm), providing a technological basis for reducing inter-string distances. Specifically, this insulating adhesive exhibits characteristics such as transparency, high insulation rate, high resistivity, and high buffering performance. Using this adhesive can effectively reduce the inter-string distance between solar cell strings and protect the solar cell silicon wafers from damage caused by lamination and encapsulation pressure and outdoor stress, thus serving a dual purpose as an insulating adhesive.

[0050] Optionally, the multifunctional acrylic resin includes at least one of tricyclodecanediethanol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, bis(trimethylolpropane)tetraacrylate, dipolypentaerythritol polyacrylate, and epoxidized dipolypentaerythritol polyacrylate.

[0051] Optionally, the epoxy resin includes at least one of bisphenol A type epoxy resin and alicyclic epoxy resin.

[0052] Optionally, specific active toughening agents include various blends of long-chain linear glycidyl ether epoxy resins and polyester polyols.

[0053] Optionally, the coupling agent includes at least one of silane coupling agents, silane oligomers, and titanate coupling agents.

[0054] Optionally, the softener includes polycarbonate with a molecular weight range of 500-6000.

[0055] Optionally, the additives include leveling agents and defoamers; wherein the leveling agent accounts for 0.1% to 0.5% of the mass percentage of the insulating adhesive used for solar cell strings; and the defoamer accounts for 0.1% to 0.5% of the mass percentage of the insulating adhesive used for solar cell strings.

[0056] Optionally, the leveling agent includes at least one of silicone-modified polyether leveling agents and silicone leveling agents; and / or, the defoamer includes at least one of polyether defoamers and silicone defoamers.

[0057] Optionally, the photoinitiator includes at least one of benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide (TBPB), and tert-butyl percarbonate-2-ethylhexyl (TBEC).

[0058] Optionally, the dispersant includes at least one of anionic and nonionic dispersants. For example, anionic dispersants may include, but are not limited to, sodium dodecylbenzenesulfonate and sodium polyacrylate.

[0059] Optionally, the pigment includes at least one of titanium dioxide, barium sulfate, cadmium red, iron oxide red, scarlet, carbon black, copper chromium black, iron chromium black, cobalt chromium blue, phthalocyanine blue, malachite green, and phthalocyanine green.

[0060] Optionally, the ultraviolet absorber includes at least one of triazine-type ultraviolet absorbers and benzophenone-type ultraviolet absorbers.

[0061] Based on the same inventive concept, embodiments of the present invention also provide a solar cell string, which includes an insulating component made of insulating adhesive for solar cell strings as provided in any of the embodiments of the present invention. Exemplarily, multiple solar cells in the solar cell string can be connected in series to form a battery string, thereby achieving series current collection and output. For example, the series connection of solar cells can be achieved by setting solder strips (busbars, interconnecting strips), conductive backplates, etc. Exemplarily, the insulating component can be understood as an insulating film layer formed after the insulating adhesive has cured. Exemplarily, the insulating component can be located at opposite ends of the solar cell string in the series direction. Figure 1 This is a top view schematic diagram showing the coating relationship between an insulating adhesive for a solar cell string and the corresponding solar cell string, according to an embodiment of the present invention. Figure 2 This is a side view schematic diagram of the coating relationship between an insulating adhesive for a solar cell string and the corresponding solar cell string, provided in an embodiment of the present invention. Figure 1 and Figure 2 As shown, the left and right edges of the solar cell string 10 are covered with a layer of insulating adhesive 20 as described in the above embodiment of the present invention (corresponding to the dotted box area in the figure) to reduce the inter-string distance between adjacent solar cell strings 10. The arrangement is carried out according to different patterns, and other components are produced in the normal process.

[0062] It is understood that in such embodiments, the battery assembly may further include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film can fill the front and back of the solar cell string, as well as between the photovoltaic glass and adjacent cells. As a filler, it can be a transparent colloid with good light transmittance and aging resistance; for example, the encapsulating film can be EVA film or POE film, and the specific choice can be made according to actual conditions, without limitation. The photovoltaic glass can cover the encapsulating film on the front of the solar cell string. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, the light transmittance of ultra-clear glass can reach over 92%, which can protect the solar cell string without affecting its efficiency as much as possible. Simultaneously, the encapsulating film can bond the photovoltaic glass and the solar cell string together, and its presence can seal, insulate, and waterproof the solar cell string. A backsheet can be attached to the encapsulating film on the back of the solar cell string. The backsheet protects and supports the solar cell string, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, aluminum alloy TPT composite encapsulating film, etc., and the specific choice depends on the specific circumstances and is not limited here. The backsheet, solar cell string, encapsulating film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame. Exemplarily, the battery module may include a front glass layer, a front encapsulating film layer, a solar cell string, a rear encapsulating film layer, and a back glass layer (or, as the backsheet), stacked sequentially from top to bottom.

[0063] Optionally, the insulating adhesive can be applied to the two opposite ends of the solar cell string in the series direction, and the application process of the insulating adhesive includes any one or a combination of two or more of spraying, dipping, and printing.

[0064] Optionally, after the insulating adhesive is applied and cured, an insulating film layer is formed. At this time, the distance between adjacent solar cell strings can be 0.2-0.3 mm, for example, 0.2 mm, 0.3 mm, etc. are within this range.

[0065] Optionally, after the insulating adhesive is applied and cured, an insulating film layer is formed. At this time, the thickness of the insulating film layer or the coating thickness of the insulating adhesive can be in the range of 100-200µm, such as 100µm, 200µm, etc.

[0066] Optionally, the insulating adhesive can cover the edges of the front and back sides of the solar cell string in the series direction with a width of 2-3 mm, such as 2 mm, 3 mm, etc.

[0067] Alternatively, the front glass layer can be made of conventional high-transparency photovoltaic glass.

[0068] Optionally, the thickness of the front glass layer can be in the range of 1.3-2mm, such as 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm or 2.0mm.

[0069] Optionally, the materials of the front and rear adhesive layers include any one of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), or EVA+POE+EVA co-extruded polymer (EPE).

[0070] Control group / basic example

[0071] In a conventional design, the front glass layer can be made of high-transmittance glass with a transmittance of 94%, the front encapsulation layer can be made of POE transparent film, the rear encapsulation layer can be made of POE transparent film, and the back glass layer can be made of glazed glass with a transmittance of 94%.

[0072] The edges of the front and back of the solar cell strings are not covered with insulating adhesive. The cell module layout consists of 6 strings, with 11 solar cells per string. A gap of 0.8 mm is left between adjacent solar cells, and a gap of 0.5 mm is left between adjacent solar strings. Other specifications follow the standard layout of 132 210×183 half-cell double-glass modules. The 132 210×183 half-cell double-glass modules have a front glass layer and a back glass layer with dimensions of 2376 mm in length and 1128 mm in width. Considering the following comparative embodiment, the performance of the cell module is tested without an aluminum frame.

[0073] Example 1

[0074] In this embodiment, the front glass layer can be a high-transmittance glass with a front transmittance of 94%, the front encapsulation layer can be a POE transparent encapsulation film, the rear encapsulation layer can be a POE transparent encapsulation film, and the back glass layer can be a back-glazed glass with a transmittance of 94%.

[0075] The edges of the front and back sides of the solar cell string are coated with an insulating adhesive material provided in any one of the embodiments of the present invention, with a coating thickness of 0.1 mm. The coating process is as follows: After the solar cell string is successfully wired, suction cups are used to hold the beginning and end of the string in the series direction. Then, the long sides of the solar cell string parallel to the sides of the solder strips are immersed in an insulating adhesive bath to a depth of 2 mm for 2 seconds. One side is coated first, followed by direct curing. The coating thickness is controlled by factors such as adhesive viscosity, immersion time, and the temperature of the insulating adhesive bath. In this case, the adhesive viscosity is 5000 cps, and the bath temperature is -5℃. This results in an adhesive coverage width of 2 mm along the series direction on the edges of the front and back sides of the solar cell string, with the long side of the adhesive surface being the same as the short side length of half a cell.

[0076] The resistivity of this insulating adhesive is 10. 16 Ω•cm, with a gap of 0.8mm between adjacent solar cells and a gap of 0.3mm between adjacent solar strings. Other specifications are arranged according to the conventional layout of 132 210×183 half-cell double-glass modules, and the width of the module is reduced by 5mm.

[0077] Example 2

[0078] In this embodiment, the front glass layer can be a high-transmittance glass with a front transmittance of 94%, the front encapsulation layer can be a POE transparent encapsulation film, the rear encapsulation layer can be a POE transparent encapsulation film, and the back glass layer can be a back-glazed glass with a transmittance of 94%.

[0079] The edges of the front and back sides of the solar cell string are coated with an insulating adhesive material provided in any one of the embodiments of the present invention, with a coating thickness of 0.1 mm. The coating process is as follows: After the solar cell string is successfully wired, suction cups are used to hold the beginning and end of the string in the series direction. Then, the long sides of the solar cell string parallel to the sides of the solder strips are immersed in an insulating adhesive bath to a depth of 2 mm for 2 seconds. One side is coated first, followed by direct curing. The coating thickness is controlled by factors such as adhesive viscosity, immersion time, and the temperature of the insulating adhesive bath. In this case, the adhesive viscosity is 5000 cps, and the bath temperature is -5℃. This results in an adhesive coverage width of 2 mm along the series direction on the edges of the front and back sides of the solar cell string, with the long side of the adhesive surface being the same as the short side length of half a cell.

[0080] The resistivity of this insulating adhesive is 10. 16Ω•cm, with a gap of 0.8mm between adjacent solar cells and a gap of 0.2mm between adjacent solar strings. Other specifications are arranged according to the conventional layout of 132 210×183 half-cell double-glass modules, and the width of the module is reduced by 5.5mm.

[0081] The battery modules prepared in the control group / basic example, Example 1, and Example 2 were all placed in an environment of 25°C for testing, held at that temperature for 5 minutes, and the light source was AM1.5, 100mW / cm². 2 The voltage test range is -50V to 50V. Table 1 is a schematic table of the test results of electrical breakdown strength provided by the embodiments of the present invention. The electrical breakdown strength of the battery modules prepared by the control group / basic embodiment, embodiment 1, and embodiment 2 were also tested, and the results are shown in Table 1 below. It can be clearly seen that the electrical breakdown strength of the battery modules prepared by embodiment 1 and embodiment 2 meets the relevant standards (e.g., 1500V), while the electrical breakdown strength of the battery modules prepared by the control group / basic embodiment does not meet the relevant standards. Furthermore, in terms of electrical experimental parameters such as open-circuit voltage Voc, short-circuit current Isc, fill factor FF, and photoelectric conversion efficiency PCE, embodiment 1 and embodiment 2 also show basically the same performance as the control group / basic embodiment.

[0082] Table 1

[0083]

[0084] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0085] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An insulating adhesive for use in solar cell strings, characterized in that, include: The multifunctional acrylic resin accounts for 50% to 85% of the mass percentage in the insulating adhesive for the solar cell string. The epoxy resin accounts for 1% to 5% of the mass percentage in the insulating adhesive for the solar cell string. The active toughening agent is present in the insulating adhesive for the solar cell string at a mass percentage between 1% and 10%. The coupling agent is present in the insulating adhesive for the solar cell string at a mass percentage between 1% and 10%. The softener is present in the insulating adhesive for the solar cell strings at a mass percentage between 1% and 10%. The additives constitute 0.2% to 1% by mass in the insulating adhesive for the solar cell strings. The photoinitiator accounts for 0.5% to 1% by mass in the insulating adhesive used in the solar cell string. The dispersant is present in the insulating adhesive for the solar cell strings at a mass percentage between 0.1% and 0.5%. The pigment, by mass percentage, is between 0% and 10% in the insulating adhesive used for the solar cell strings; The ultraviolet light absorber accounts for 0% to 2% of the mass percentage in the insulating adhesive used in the solar cell string.

2. The insulating adhesive for solar cell strings according to claim 1, characterized in that, The multifunctional acrylic resin includes at least one of tricyclodecanediethanol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, bis(trimethylolpropane)tetraacrylate, dipolypentaerythritol polyacrylate, and epoxidized dipolypentaerythritol polyacrylate.

3. The insulating adhesive for solar cell strings according to claim 1, characterized in that, The epoxy resin includes at least one of bisphenol A type epoxy resin and alicyclic epoxy resin.

4. The insulating adhesive for solar cell strings according to claim 1, characterized in that, The coupling agent includes at least one of silane coupling agents, silane oligomers, and titanate coupling agents.

5. The insulating adhesive for solar cell strings according to claim 1, characterized in that, The additives include leveling agents and defoamers; wherein... The leveling agent is present in the insulating adhesive for solar cell strings at a mass percentage between 0.1% and 0.5%. The defoamer is present in the insulating adhesive for solar cell strings at a mass percentage between 0.1% and 0.5%.

6. The insulating adhesive for solar cell strings according to claim 5, characterized in that, The leveling agent includes at least one of silicone-modified polyether leveling agents and silicone leveling agents; And / or, the defoamer includes at least one of polyether defoamers and silicone defoamers.

7. The insulating adhesive for solar cell strings according to claim 1, characterized in that, The photoinitiator includes at least one of benzoyl peroxide, dicumyl peroxide, tert-butyl peroxide, and tert-butyl percarbonate-2-ethylhexyl.

8. The insulating adhesive for solar cell strings according to claim 1, characterized in that, The pigments include at least one of titanium dioxide, barium sulfate, cadmium red, iron oxide red, scarlet powder, carbon black, copper chromium black, iron chromium black, cobalt chromium blue, phthalocyanine blue, malachite green, and phthalocyanine green.

9. The insulating adhesive for solar cell strings according to claim 1, characterized in that, The ultraviolet light absorber includes at least one of triazine-type ultraviolet light absorbers and benzophenone-type ultraviolet light absorbers.

10. A solar cell string, characterized in that, Includes an insulating component, said insulating component being prepared using the insulating adhesive for solar cell strings as described in any one of claims 1-9.

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