Reflective film, preparation method of photovoltaic module and photovoltaic module

Abstract

The embodiment of the invention provides a reflective film, a preparation method of a photovoltaic module and the photovoltaic module. The reflective film is used in a photovoltaic module and is laid in a gap between adjacent battery pieces. The reflective film comprises a base layer; the reflective layer is stacked on the surface of the base layer, and the reflective layer is used for reflecting light; the first bonding layer is stacked on the surface, deviating from the base layer, of the light reflecting layer; the first bonding layer is made of an insulating adhesive resin material. According to the embodiment of the invention, the insulating adhesive resin material is arranged on the reflective layer of the reflective film to serve as the first bonding layer, so that the first bonding layer can be independently used for coating the reflective layer, and a certain insulating thickness between the reflective film and the battery piece is ensured; and the problem of local short circuit of the photovoltaic module caused by insufficient insulation thickness due to factors such as large lamination edge stress of the photovoltaic module is solved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a reflective film, a method for preparing a photovoltaic module, and a photovoltaic module. Background Art

[0002] The photovoltaic module includes multiple cells. By setting a reflective film in the gaps between the multiple cells, the sunlight that hits the back glass can be reflected back to the cells, thereby absorbing more light energy and improving the photoelectric conversion efficiency of the photovoltaic module.

[0003] The most commonly used materials for reflective film include aluminum, which is a metal material with conductive properties. When the reflective film contacts the solar cell, it is easy to cause a short circuit, reducing the output power of the photovoltaic module.

[0004] At present, the packaging film between the back glass and the cell is usually relied on, which can be melted and filled between the reflective film and the cell during lamination to achieve insulation between the reflective film and the cell. However, due to the high stress in the edge area of ​​the photovoltaic module during the lamination packaging process, the thickness of the packaging film in the edge area is thinner, and the thickness of the insulating layer between the reflective film and the cell is thinner, making it difficult to achieve insulation between the reflective film and the cell.

[0005] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0006] The embodiments of the present application provide a reflective film, a method for preparing a photovoltaic module, and a photovoltaic module to solve or alleviate one or more of the technical problems mentioned above.

[0007] In a first aspect, an embodiment of the present application provides a reflective film, which is used in a photovoltaic module and laid in the gap between adjacent solar cells, comprising: Grassroots; A reflective layer, which is stacked on the surface of the base layer and is used to reflect light; The first adhesive layer is stacked on the surface of the reflective layer away from the base layer; the first adhesive layer is made of insulating adhesive resin material.

[0008] Optionally, it further comprises a second adhesive layer, which is stacked on the surface of the base layer away from the reflective layer; the second adhesive layer is made of insulating thermoplastic rubber.

[0009] Optionally, the insulating adhesive resin includes a thermosetting resin or a photocurable resin; the thermosetting resin includes one or more of acrylate, epoxy resin and polyurethane; the photocurable resin includes one or more of acrylate, epoxy resin and polyurethane.

[0010] Optionally, the thickness of the first adhesive layer is 0.01% to 25% of the width of the reflective layer.

[0011] Optionally, the thickness of the first adhesive layer is 10 μm to 200 μm.

[0012] A second aspect of an embodiment of the present application provides a method for preparing a photovoltaic module, comprising: Obtaining a front glass, and sequentially stacking a first packaging adhesive film, a plurality of battery cells evenly spaced apart, and a second packaging adhesive film on the front glass; wherein each battery cell has a gap with an adjacent battery cell; Obtaining a back glass, and stacking a reflective film on the back glass, wherein the reflective film comprises a second adhesive layer, a base layer, a reflective layer and a first adhesive layer stacked in sequence; Plasma treatment is performed on the reflective film so that the second adhesive layer is bonded to the back glass; The side of the back glass laminated with the reflective film is covered on the second packaging film, and the reflective film is arranged corresponding to the gap to obtain a laminated component corresponding to the photovoltaic component.

[0013] Optionally, obtaining a laminate assembly corresponding to the photovoltaic assembly further includes: The first adhesive layer is cured; the curing process includes heating the reflective film at a preset temperature, or irradiating the reflective film with a light source; The stacked components corresponding to the photovoltaic components are obtained, and then the stacked components are laminated to obtain the photovoltaic components.

[0014] Optionally, the plasma treatment comprises: Gas is introduced into the plasma processing equipment at a flow rate of 1.2 L / min to 1.8 L / min for 10 seconds to 600 seconds, so that the pressure in the plasma processing equipment is 0.8 atm to 1.2 atm.

[0015] Optionally, the packaging film has a thickness of 150 μm to 300 μm.

[0016] Optionally, the length of the reflective film is 88%-95% of the dimension of the back glass in the extending direction of the reflective film.

[0017] A third aspect of an embodiment of the present application provides a photovoltaic module, which is prepared using the preparation method described above.

[0018] The above technical solution adopted in the embodiment of the present application may have the following advantages: By arranging an insulating adhesive resin material as the first bonding layer on the reflective layer of the reflective film, the first bonding layer can be used independently to cover the reflective layer, thereby ensuring a certain insulation thickness between the reflective film and the battery cell, and preventing the problem of partial short circuit of the photovoltaic module due to insufficient insulation thickness due to factors such as large stress on the lamination edge of the photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0020] Figure 1 1 is a structural diagram of a reflective film provided in an embodiment of the present invention; Figure 2 is a flow chart of a method for preparing a photovoltaic module provided in an embodiment of the present application; Figure 3 is an EL diagram of a photovoltaic module provided in one embodiment of the present application; Figure 4 This is an EL diagram of a photovoltaic module provided in a ratio in this application. DETAILED DESCRIPTION

[0021] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. Wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0022] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. When the second element, component, region, layer or part is discussed, it does not indicate that the present application necessarily has the first element, component, region, layer or part.

[0023] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0026] Hereinafter, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. It should be noted that these exemplary embodiments can be implemented in many different forms and should not be construed as being limited to the embodiments described herein.

[0027] like Figure 1 As shown, an embodiment of the present application provides a reflective film, which is used in a photovoltaic module and laid in the gap between adjacent solar cells, and includes a base layer 120 , a reflective layer 110 and a first adhesive layer 100 .

[0028] The reflective layer 110 is stacked on the surface of the base layer 120 , and the reflective layer 110 is used for reflecting light.

[0029] The first adhesive layer 100 is stacked on the surface of the reflective layer 110 that is away from the base layer 120 ; the first adhesive layer 100 is made of an insulating adhesive resin material.

[0030] Reflective films include metal reflective films and plastic reflective films. Since plastic reflective films have a higher refractive index, refraction loss occurs during the reflection of light, so the light utilization rate is relatively lower than that of metal reflective films. In addition, the weather resistance of plastic reflective films is not as high as that of metal reflective films. When photovoltaic modules are exposed to outdoor environments for a long time, plastic reflective films may age, discolor, or suffer surface damage. Therefore, metal reflective films can be used in photovoltaic modules.

[0031] In a photovoltaic module, a reflective film is arranged in the gap area between adjacent cells, with the reflective surface of the reflective film facing the front glass; on the one hand, it can improve the compactness of the structure inside the photovoltaic module, and on the other hand, it can reflect light, so that when the light entering from the front glass is directed toward the back glass, the light irradiated on the reflective film can be reflected back and absorbed by the cells for use. Therefore, by arranging a reflective film in the gap between the cells, multiple utilization of light can be achieved, and the photoelectric conversion efficiency of the photovoltaic module can be improved.

[0032] In one example, the base layer 120 may be made of PET (Polyethylene Terephthalate), which has high strength, rigidity and heat resistance, and is blow-molded to form the base layer 120 of the reflective film.

[0033] In one example, PET can be prepared into a structure with a pyramidal surface. The light is reflected multiple times on the pyramidal surface, which can increase the light absorption rate.

[0034] In one example, the base layer 120 may also be made of acrylic photocurable adhesive.

[0035] The reflective layer 110 can be an aluminum film with high reflectivity. The aluminum film is laid on the pyramid-shaped morphology of the base layer 120 to increase the reflective effect of the reflective film. More light can be reflected onto the battery cell, thereby improving the photoelectric conversion efficiency.

[0036] The first adhesive layer 100 covers the surface of the reflective layer 110 to ensure that there is sufficient insulation thickness between the reflective film and the cell. There is a gap between the reflective film and the cell, so the adhesive film independently covering the reflective layer 110 will only wrap around the reflective layer 110 after melting, and is not easily affected by edge stress.

[0037] In an exemplary application scenario, the reflective film provided by the embodiments of the present application may be laid at all locations in the photovoltaic module where reflective film can be laid.

[0038] In an exemplary application scenario, the reflective film laid in the edge area of ​​the photovoltaic module can be the reflective film provided in the embodiment of the present application. When the photovoltaic module is encapsulated, after the reflective film is laid in the gap between adjacent cells, a layer of encapsulation film will be laid to bond the encapsulation glass. When the encapsulation film is laminated and encapsulated in the photovoltaic module, it is melted and covered on the surface of the reflective film and the cell. The molten film can be used as an insulating material to cover the reflective film, which can prevent the conductive reflective layer 110 from contacting the cell and causing the photovoltaic module to short-circuit. However, in the edge area of ​​the photovoltaic module, due to the large stress, the film retained after lamination is thin, the insulation thickness between the reflective film and the cell is insufficient, and a short circuit is prone to occur. Therefore, by laying the reflective film in the edge area of ​​the photovoltaic module as the reflective film provided in the embodiment of the present application, the insulation thickness between the reflective film and the cell can be enhanced to avoid short circuits.

[0039] In the embodiment of the present application, by providing the first adhesive layer 100 on the reflective layer 110, the first adhesive layer 100 can be used independently to cover the reflective layer 110, thereby ensuring the insulation thickness between the reflective film and the battery cell, and preventing the problem of short circuit caused by insufficient insulation thickness due to stress factors in the edge area during lamination.

[0040] In an optional embodiment, the reflective film further includes a second adhesive layer 130 , which is stacked on a surface of the base layer 120 that is away from the reflective layer 110 ; the second adhesive layer 130 is made of insulating thermoplastic rubber.

[0041] The second adhesive layer 130 is stacked on the surface of the base layer 120 facing away from the reflective layer 110 , that is, the second adhesive layer 130 is located at the (bottom) layer of the reflective film. The second adhesive layer 130 contacts the back glass in the photovoltaic module to form a bonding interface.

[0042] The second adhesive layer 130 can be made of a material having an adhesive function after lamination. The second adhesive layer 130 can firmly adhere the reflective film to the film layer in contact with it to prevent the reflective film from moving.

[0043] In the embodiment of the present application, by disposing the second adhesive layer 130 at the bottom of the reflective film, the reflective film can be stably laid in the gap between the battery cells and will not move close to the battery cells due to external forces during the lamination process.

[0044] In an optional embodiment, the insulating adhesive resin includes a thermosetting resin or a photocurable resin; the thermosetting resin includes one or more of acrylate, epoxy resin and polyurethane; the photocurable resin includes one or more of acrylate, epoxy resin and polyurethane.

[0045] Light-curable resins can be quickly cured by ultraviolet light or other visible light to form a stable adhesive layer.

[0046] In one example, the insulating adhesive resin can be a light-curable acrylic resin, which is a viscous liquid before curing and has low fluidity. After the light-curable acrylic resin is coated on the surface of the reflective layer 110 away from the base layer 120, it is cured after being irradiated with ultraviolet rays to form a stable first adhesive layer 100.

[0047] Thermosetting resins can be quickly cured by heating at high temperatures to form a stable bonding layer.

[0048] In one example, the thermosetting resin may be an epoxy resin. Before curing, the epoxy resin may be in a viscous liquid state with low fluidity. After the epoxy resin is coated on the surface of the reflective layer 110 away from the base layer 120, it is subjected to high temperature heating treatment on a heating platform and cured to form a stable first adhesive layer 100.

[0049] In this embodiment, the chemical reaction of the photocurable resin / thermocurable resin during the curing process is irreversible, thereby forming a stable structure that can remain solid even during high-temperature lamination, so that the insulating thickness of the reflective film does not change, thereby improving the stability of the photovoltaic module.

[0050] In an optional embodiment, the thickness of the first adhesive layer 100 is 0.01% to 25% of the width of the reflective layer 110 .

[0051] In this embodiment, the wider the reflective layer 110 is, the thicker the first adhesive layer 100 is, so as to ensure that there is enough molten adhesive film to cover the reflective layer 110 .

[0052] In one example, the ratio between the thickness of the first adhesive layer 100 and the width of the reflective layer 110 may be determined based on the required insulation thickness between the reflective film and the cell.

[0053] In one example, in a scenario where product stability is required to be higher, a thicker first adhesive layer 100 can be selected to ensure insulation between the reflective film and the cell. The thickness of the first adhesive layer 100 is less than 25% of the width of the reflective layer 110, because the width of the reflective layer 110 is limited, and too wide will occupy the space of the cell. Under the limited width of the reflective layer 110, the thickness of the first adhesive layer 100 reaching 25% of the width of the reflective layer 110 is sufficient to meet the requirements and will not cause bumps.

[0054] In one example, in a scenario where the power generation efficiency of the photovoltaic module is required to be higher, a thinner thickness of the first adhesive layer 100 can be selected so that the width of the reflective layer 110 can be wider and more reflected light is absorbed by the photovoltaic module. However, the thickness of the first adhesive layer 100 still needs to meet the limit of being greater than 0.01% of the width of the reflective layer 110 to avoid the first adhesive layer 100 being too thin and unable to play an insulating effect.

[0055] The ratio of the thickness of the first adhesive layer 100 to the width of the reflective layer 110 is limited, and can also be adaptively adjusted according to the material properties of the first adhesive layer 100, so that the thickness of the first adhesive layer 100 is adjusted within a reasonable controllable range. For example, when the first adhesive layer 100 has strong fluidity after melting, the ratio of the thickness of the first adhesive layer 100 to the width of the reflective layer 110 can be smaller.

[0056] In one example, according to the material properties of the first adhesive layer 100 and the application scenario requirements, a preset ratio of the thickness of the first adhesive layer 100 to the width of the reflective layer 110 can be determined. For example, the preset ratio can be 0.01%, 0.1%, 10%, 12%, 16% or 25%.

[0057] In actual operation, the thickness of the first adhesive layer 100 in the multiple reflective films can be close to a preset ratio of the width of the reflective layer 110, so that the first adhesive layer 100 can be coated under this benchmark, and the average value of the ratio of the thickness of the first adhesive layer 100 of the multiple reflective films to the width of the reflective layer 110 can reach the preset ratio.

[0058] In an optional embodiment, the thickness of the first adhesive layer 100 is 10 μm to 200 μm. Exemplarily, the thickness of the first adhesive layer 100 is 10 μm, 50 μm, 100 μm, 150 μm or 200 μm.

[0059] Based on the aforementioned ratio limit of the thickness of the first adhesive layer 100 to the width of the reflective layer 110, the thickness of the first adhesive layer 100 can be determined. The determined thickness of the first adhesive layer 100 still needs to meet its actual thickness limit, such as a thickness within 10μm~200μm. Avoid the situation where the thickness of the first adhesive layer 100 is too thick due to the selected reflective layer 110 being too wide and the ratio being too large; similarly, avoid the situation where the thickness of the first adhesive layer 100 is too thin.

[0060] In one example, a large piece of reflective film may be made first, and then the reflective film with a preset width may be cut and laid in the gap between the battery cells; the preset width is adapted to the width of the gap between the battery cells.

[0061] like Figure 2As shown, the embodiment of the present application can also provide a method for preparing a photovoltaic module, comprising: S200: Obtain a front glass, and sequentially stack a first packaging film, a plurality of battery cells evenly spaced apart, and a second packaging film on the front glass; wherein a gap is provided between each battery cell and adjacent battery cells.

[0062] S210: obtaining a back glass, and stacking a reflective film on the back glass, wherein the reflective film comprises a second adhesive layer, a base layer, a reflective layer, and a first adhesive layer stacked in sequence.

[0063] S220: Plasma treatment is performed on the reflective film to bond the second adhesive layer to the rear glass.

[0064] S230: Covering the side of the back glass with the reflective film on top of the second packaging film, and setting the reflective film corresponding to the gap to obtain a laminated component corresponding to the photovoltaic component.

[0065] In one example, the material of the first packaging film and / or the second packaging film may be EPE (Expanded Polyethylene) or EVA (Ethylene-Vinyl Acetate).

[0066] A reflective film is stacked on the gap area between the adjacent cells corresponding to the back glass. The gap area between the adjacent cells is a light-transmitting area, and light can directly irradiate from the front glass to the back glass. Therefore, a reflective film can be set in the gap area to reflect the light irradiated on the back glass back to the cells to improve the photoelectric conversion efficiency of the photovoltaic module.

[0067] The reflective film includes a second adhesive layer, a base layer, a reflective layer and a first adhesive layer stacked on the back glass in sequence. The first adhesive layer can ensure the insulation thickness between the reflective film and the battery cell to prevent the reflective film from contacting the battery cell and causing a short circuit.

[0068] Before laying the reflective film on the back glass, the reflective film is subjected to plasma treatment. Plasma treatment applies a high-frequency electric field or microwave to the gas to ionize the gas to form plasma. The plasma reacts with the side of the second adhesive layer of the reflective film that contacts the back glass, thereby firmly fixing the reflective film on the surface of the back glass and preventing the reflective film from moving in subsequent processes.

[0069] In one example, the gas used in the plasma treatment may be oxygen, and the second adhesive layer may be ethylene-vinyl acetate copolymer. Polar oxygen-containing groups (such as hydroxyl groups, carbonyl groups, etc.) in the oxygen plasma react with the ethylene-vinyl acetate copolymer to form hydrogen bonds or covalent bonds, thereby increasing the bonding performance of the second adhesive layer to the back glass.

[0070] In this embodiment, by performing plasma treatment on the reflective film in the photovoltaic module, the bonding performance between the reflective film and the back glass can be enhanced, thereby increasing the stability of the photovoltaic module.

[0071] In an optional embodiment, obtaining a laminate assembly corresponding to the photovoltaic assembly further includes: The first adhesive layer is cured; the curing process includes heating the reflective film at a preset temperature, or irradiating the reflective film with a light source; The stacked components corresponding to the photovoltaic components are obtained, and then the stacked components are laminated to obtain the photovoltaic components.

[0072] In one example, the first adhesive layer may be a thermosetting epoxy resin. At this time, the corresponding curing process may be: heating the reflective film at a preset temperature to cure the thermosetting epoxy resin. The preset temperature may be 80°C to 200°C, and heating is performed at the preset temperature for 15 minutes to 60 minutes. During the heating process, the thermosetting epoxy resin undergoes a cross-linking reaction, cross-linking bonds are formed between the molecular chains, and finally a three-dimensional network structure is formed, and the thermosetting epoxy resin changes from a liquid state to a solid state.

[0073] In one example, the first adhesive layer may be a photocurable acrylate resin. At this time, the corresponding curing process may be: using a light source to irradiate the reflective film. The light source may be an ultraviolet curing lamp, and the ultraviolet intensity may be 3000mJ / s. After irradiation for 0.5s to 10s, the photocurable acrylate resin absorbs light energy and undergoes a polymerization reaction, thereby curing to form a stable polymer structure. Specifically, after the photosensitizer in the photocurable acrylate resin absorbs light energy, the molecular structure changes and free radicals are generated, and the free radicals initiate the polymerization reaction of the resin. During the polymerization process, a cross-linking reaction occurs between the resin molecular chains to form a three-dimensional network structure, so that the photocurable resin changes from a liquid state to a solid state.

[0074] In one example, the stack assembly may be laminated using various technical solutions known to those skilled in the art now and in the future, which will not be described in detail here.

[0075] In this embodiment, the first adhesive layer is cured to form a reflective film with good insulation performance, which can avoid the reflective film contacting the battery cell to cause a short circuit, thereby increasing the stability of the photovoltaic module.

[0076] In an optional embodiment, the plasma treatment includes: introducing gas into the plasma treatment equipment at a flow rate of 1.2L / min~1.8L / min for a time of 10 seconds~600 seconds, so that the pressure in the plasma treatment equipment is 0.8atm~1.2atm.

[0077] In one example, the gas introduced into the plasma processing equipment may be oxygen, argon, or a mixture thereof.

[0078] The flow rate of the incoming gas is 1.2L / min~1.8L / min. If the flow rate of the incoming gas is too large, the plasma in the equipment will be diluted, the density of the plasma will be reduced, the treatment effect of the reflective film surface will be poor, and the improvement of the bonding performance will be limited. If the flow rate of the incoming gas is too small, the plasma formed by ionization in the gas will be insufficient, which will also lead to poor treatment effect. Therefore, it is necessary to limit the flow rate of the incoming gas within a certain range.

[0079] The gas introduction time is 10 seconds to 600 seconds. If the gas introduction time is too short, the plasma reaction may be insufficient, while if the gas introduction time is too long, the material surface may be damaged, affecting the plasma treatment effect.

[0080] During the plasma treatment process, higher pressure can increase the density of gas molecules and the number of active particles (such as ions and free radicals) accordingly, thereby improving the treatment effect. However, if the pressure is too high, it will lead to over-treatment and damage the material surface, while if the pressure is too low, the gas density will be insufficient, and fewer active particles will affect the treatment effect. Therefore, the pressure in the plasma treatment equipment can be controlled within the range of 0.8atm~1.2atm.

[0081] In one example, the plasma treatment can also be performed on the surface of the glass on the back side of the glass to increase the wettability of the surface of the glass on the back side and further improve the bonding performance between the reflective film and the surface of the glass on the back side.

[0082] In this embodiment, by limiting the flow rate and time of the gas introduced into the plasma treatment and the pressure in the plasma treatment equipment within a certain range, the effect of the plasma treatment can be improved, the bonding performance between the reflective film and the back glass can be further improved, and the photovoltaic module can be made more stable.

[0083] In an optional embodiment, the thickness of the packaging film is 150 μm to 300 μm. For example, the thickness of the packaging film may be 150 μm, 180 μm, 200 μm, 250 μm or 300 μm.

[0084] In one example, a photovoltaic module includes a back glass, a reflective film laid on the back glass, a packaging film laid on the surface of the reflective film, and a cell laid on the surface of the packaging film. During high-temperature lamination, the packaging film melts to the surface of the reflective film and forms an insulating layer of the reflective film. However, due to the large lamination stress at the edge of the photovoltaic module, the thickness of the insulating layer is insufficient, and the packaging film needs to be thickened, generally adding an additional 20 to 50 grams per square meter of film, which increases the manufacturing cost.

[0085] In this embodiment, the packaging film is provided with a reflective film of the first adhesive layer, and the thickness of the packaging film does not need to be increased to ensure that the reflective film has sufficient insulation performance. Therefore, cost can be saved while ensuring the stability of the photovoltaic module.

[0086] In an optional embodiment, the length of the reflective film is 88%-95% of the size of the back glass in the extending direction of the reflective film. Exemplarily, the length of the reflective film can be 88%, 90%, 92% or 95% of the size of the back glass in the extending direction of the reflective film.

[0087] In one example, if the long side of the back glass is 2 meters and the length of the reflective film is 90% of the long side of the back glass, the corresponding length of the reflective film may be 1.8 meters.

[0088] Since the edge area of ​​the photovoltaic module is subjected to greater stress, the adhesive film retained after lamination is relatively thin, and the insulation thickness between the reflective film and the cell is insufficient, which is prone to short circuit. However, by laying the reflective film provided by the embodiment of the present application on the edge area of ​​the photovoltaic module, the insulation thickness between the reflective film and the cell can be enhanced. The reflective film can be laid to the edge area of ​​the back glass, so that the laying length of the reflective film can reach 88%-95% of the size of the back glass in the extension direction of the reflective film.

[0089] In this embodiment, by laying the reflective film with a length between 88% and 95% of the size of the back glass in the extension direction of the reflective film, the surface area of ​​the back glass can be fully utilized to improve the compactness of the internal structure of the photovoltaic module, and increase the probability of light being reflected back to the internal battery, thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0090] The following will conduct performance tests on the preparation methods of the reflective films or photovoltaic modules provided in the embodiments of the present application and related comparative examples.

[0091] [Example 1] The specific preparation process of photovoltaic modules is as follows: Step 1: Obtain front glass, lay a first packaging film on the front glass in sequence, stack cells on the first packaging film according to preset rules, with a gap between each cell and adjacent cells, and then lay a second packaging film on the cells.

[0092] Step 2: Obtain a reflective film, which includes a second adhesive layer, a base layer, and a reflective layer stacked in sequence, and perform plasma treatment on the second adhesive layer in the reflective film. Oxygen and argon are introduced into the plasma equipment at a flow rate of 1.2 L / min for 10 seconds, and the gas pressure inside the plasma equipment is 1 atm.

[0093] Step 3: coating a first adhesive layer on the surface of the reflective layer in the reflective film obtained in step 2, wherein the first adhesive layer is thermosetting acrylate.

[0094] Step 4: The reflective film obtained in step 3 is heated and cured at a temperature of 80° C. for 30 minutes.

[0095] Step 5: Obtain a back glass, and lay the second adhesive layer of the reflective film obtained in step 4 toward the back glass. The reflective film is arranged in the gap area between the cells in step 1.

[0096] Step 6: Place the side of the back glass with the reflective film toward the second packaging film in step 1 to obtain a stacked assembly corresponding to the photovoltaic assembly, and laminate the stacked assembly to obtain a photovoltaic assembly.

[0097] [Example 2] The only difference from Example 1 is that step 3 of Example 2 is: coating a first adhesive layer on the surface of the reflective layer in the reflective film obtained in step 2, wherein the first adhesive layer is a thermosetting epoxy resin.

[0098] [Example 3] The only difference from Example 1 is that step 3 of Example 3 is: coating a first adhesive layer on the surface of the reflective layer in the reflective film obtained in step 2, wherein the first adhesive layer is thermosetting polyurethane.

[0099] [Example 4] The only difference from Example 1 is that step 4 of Example 4 is: the reflective film obtained in step 3 is subjected to a heating and curing treatment at a temperature of 100° C. for a treatment time of 20 minutes.

[0100] [Example 5] The only difference from Example 1 is that step 4 of Example 5 is: the reflective film obtained in step 3 is subjected to a heating and curing treatment at a temperature of 150° C. for a treatment time of 15 minutes.

[0101] [Example 6] The only difference from Example 1 is that step 3 of Example 6 is: coating the surface of the reflective layer in the reflective film obtained in step 2 with a first adhesive layer, wherein the first adhesive layer is a light-curable acrylate. Step 4 is: performing a light-curing treatment on the reflective film obtained in step 3. The ultraviolet irradiation is performed with an intensity of 3000 mJ / s and the irradiation time is 1 second.

[0102] [Example 7] The only difference from Example 1 is that step 2 in Example 7 does not include plasma treatment of the second bonding layer.

[0103] [Example 8] The only difference from Example 2 is that step 2 in Example 8 does not include plasma treatment of the second bonding layer.

[0104] [Comparative Example 1] The specific preparation process of photovoltaic modules is as follows: Step 1: Obtain front glass, lay a first packaging film on the front glass in sequence, stack cells on the first packaging film according to preset rules, with a gap between each cell and adjacent cells, and then lay a second packaging film on the cells.

[0105] Step 2: Obtain a reflective film, which includes a second adhesive layer, a base layer, and a reflective layer stacked in sequence, and perform plasma treatment on the second adhesive layer in the reflective film. Oxygen and argon are introduced into the plasma equipment at a flow rate of 1.2 L / min for 10 seconds, and the gas pressure inside the plasma equipment is 1 atm.

[0106] Step 3: Obtain back glass and reflective film, the reflective film includes an adhesive layer, a base layer, and a reflective layer stacked in sequence, and the adhesive layer is laid toward the back glass. The reflective film is arranged in the gap area between the cells in step 1.

[0107] Step 4: Place the side of the back glass provided with the reflective film toward the second packaging film in step 1 to obtain a laminated assembly corresponding to the photovoltaic assembly, and laminate the laminated assembly to obtain a photovoltaic assembly.

[0108] [Comparative Example 2] The only difference from Comparative Example 1 is that in step 2 of Comparative Example 2, oxygen and argon are introduced into the plasma equipment at a flow rate of 1.5 L / min for 8 seconds, and the gas pressure inside the plasma equipment is 1 atm.

[0109] [Comparative Example 3] The only difference from Comparative Example 1 is that step 2 in Comparative Example 3 does not include plasma treatment of the second bonding layer.

[0110] The following is a performance test of the photovoltaic modules provided in Examples 1 to 8 of the present application and Comparative Examples 1 to 3, so as to obtain the power W of the corresponding photovoltaic modules, the bonding force N / cm between the reflective film and the back glass, and after baking the corresponding photovoltaic modules at 150°C for 48 hours, check whether the reflective film is delaminated. The test results are shown in Table 1.

[0111] It should be noted that the data increase / decrease in the power test is relative to the test results of conventional double-glass photovoltaic modules without reflective film; the test results are shown in Table 1: Table 1. Test data of photovoltaic modules of Examples 1 to 8 and Comparative Examples 1 to 3

[0112] In addition, the present application also provides EL (Electroluminescence Image) images of the photovoltaic modules provided in Example 1 and Comparative Example 2. The EL image of the photovoltaic module provided in Example 1 is as follows: Figure 3 As shown, the EL diagram of the photovoltaic module provided in Comparative Example 2 is as follows Figure 4 shown.

[0113] As can be seen from Table 1, the power increase of the photovoltaic modules of Examples 1 to 8 is significantly increased compared with that of Comparative Examples 1 to 3, and Comparative Examples 1 to 3 are more likely to have a significant power attenuation (short circuit) phenomenon because the reflective film of the embodiment of the present application is not used. The adhesive force of Examples 1 to 6 and Comparative Examples 1 to 2, in which the reflective film is treated with plasma, is significantly improved compared with Examples 7 to 8 and Comparative Example 3, in which the reflective film is not treated with plasma, and the probability of delamination of the reflective film after baking for 48 hours is significantly reduced. In other words, after the reflective film is treated with plasma, the bonding performance with the back glass is better.

[0114] The embodiment of the present application may also provide a photovoltaic module, which is prepared by the above-mentioned method for preparing the photovoltaic module.

[0115] The embodiment of the present application can provide a photovoltaic system, including the photovoltaic components in any of the above embodiments. The advantages of the above photovoltaic components are also possessed by the photovoltaic system, which will not be repeated here. The above photovoltaic system has a wide range of applications, not only limited to photovoltaic power stations, such as ground power stations, rooftop power stations and water power stations, but also includes various equipment and devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars and solar buildings. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be used in all fields where solar energy is required for power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components may form multiple photovoltaic arrays. The photovoltaic array is connected to a junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid, and then connected to the mains network to realize solar power supply.

[0116] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0117] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0118] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0119] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A reflective film, characterized in that: Used in photovoltaic modules and laid in the gaps between adjacent cells, including: Grassroots; A reflective layer, which is stacked on the surface of the base layer and is used to reflect light; The first adhesive layer is stacked on the surface of the reflective layer away from the base layer; the first adhesive layer is made of insulating adhesive resin material.

2. The reflective film according to claim 1, characterized in that: It also includes a second adhesive layer, which is stacked on the surface of the base layer away from the reflective layer; the second adhesive layer is made of insulating thermoplastic rubber.

3. The reflective film according to claim 1, characterized in that: The insulating adhesive resin includes a thermosetting resin or a photocurable resin; the thermosetting resin includes one or more of acrylate, epoxy resin and polyurethane; the photocurable resin includes one or more of acrylate, epoxy resin and polyurethane.

4. The reflective film according to claim 1, characterized in that: The thickness of the first adhesive layer is 0.01% to 25% of the width of the reflective layer.

5. The reflective film according to claim 4, characterized in that: The thickness of the first adhesive layer is 10 μm to 200 μm.

6. A method for preparing a photovoltaic module, characterized in that: The method comprises: Obtain a front glass, and sequentially stack a first packaging adhesive film, a plurality of battery cells evenly spaced and distributed, and a second packaging adhesive film on the front glass; wherein a gap exists between each of the battery cells and the adjacent battery cells; Obtaining a back glass, and stacking a reflective film on the back glass, wherein the reflective film comprises a second adhesive layer, a base layer, a reflective layer and a first adhesive layer stacked in sequence; Performing plasma treatment on the reflective film so that the second adhesive layer is bonded to the back glass; The side of the back glass stacked with the reflective film is covered on top of the second packaging film, and the reflective film is arranged corresponding to the gap to obtain a stacked assembly corresponding to the photovoltaic assembly.

7. The preparation method according to claim 6, characterized in that: The step of obtaining a laminated assembly corresponding to the photovoltaic assembly also includes: The first adhesive layer is subjected to a curing treatment; the curing treatment includes heating the reflective film at a preset temperature, or irradiating the reflective film with a light source; The method of obtaining a laminated assembly corresponding to the photovoltaic assembly further includes: laminating the laminated assembly to obtain the photovoltaic assembly.

8. The preparation method according to claim 6, characterized in that: The plasma treatment comprises: A gas is introduced into the plasma processing equipment at a flow rate of 1.2 L / min to 1.8 L / min for a time of 10 seconds to 600 seconds, so that the pressure in the plasma processing equipment is 0.8 atm to 1.2 atm.

9. The preparation method according to claim 6, characterized in that: The thickness of the packaging film is 150 μm to 300 μm.

10. The preparation method according to claim 6, characterized in that: The length of the reflective film is 88% to 95% of the dimension of the back glass in the extending direction of the reflective film.

11. A photovoltaic module, characterized in that: The method is prepared according to any one of claims 6 to 10.

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