A bifacial photovoltaic module and a method of manufacturing the same

Abstract

The application provides a bifacial photovoltaic module and a preparation method thereof. The bifacial photovoltaic module comprises at least a front encapsulation plate, a front transparent adhesive film, a cell piece layer, a back transparent adhesive film and a back encapsulation plate which are arranged in a stack, and a light reflection layer is further arranged between the cell piece layer and the back encapsulation plate. The light reflection layer comprises at least a first region and a second region. The cell piece layer comprises a plurality of interconnected cell strings, and each cell string is formed by connecting a plurality of cell pieces in series. The second region is arranged in a projection area of at least part of an edge area of a plurality of cell piece coverage areas on the light reflection layer, and the first region is arranged in a projection area of at least part of a non-cell piece coverage area on the light reflection layer. The front visible light reflectivity of the first region is higher than that of the second region, and the back visible light transmittance of the second region is higher than that of the first region. The bifacial photovoltaic module is additionally provided with the light reflection layer with a regional design, so that the front power generation is ensured, light leakage is avoided, and a high bifacial rate is maintained.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic module technology, and relates to a bifacial photovoltaic module, and more particularly to a bifacial photovoltaic module and its preparation method. Background Technology

[0002] Against the backdrop of the global photovoltaic industry's continuous upgrading towards higher efficiency and higher power generation, bifacial photovoltaic modules, due to their ability to simultaneously utilize incident light from the front and diffused light from the back, can increase power generation by 10%-30% compared to traditional monofacial photovoltaic modules, and have become the mainstream choice for large-scale ground-mounted power plants and distributed photovoltaic systems. However, based on the power generation principle and structural design of bifacial photovoltaic modules, they face a contradiction between "front power guarantee" and "back light transmission for power generation." This contradiction is particularly prominent in the gap areas between cells and between cell strings, becoming a key bottleneck restricting further performance improvements.

[0003] To improve the front-side light collection efficiency of traditional single-sided photovoltaic (PV) modules, engineers typically encapsulate the back side with a white EVA film and a white backsheet. This is because the white material has high diffuse reflection properties in the gaps between cells and strings, reflecting light that is not absorbed by the cells after incident on the front back to the front, supplementing the generation of photogenerated carriers and thus significantly increasing front-side power. This design perfectly suits the technical requirements of single-sided PV modules that rely solely on front-side light for power generation, and its application in the industry is mature and cost-effective.

[0004] However, the defining characteristic of bifacial photovoltaic modules is "bifacial power generation," which requires ensuring that light from the back can penetrate the encapsulation layer and reach the PN junction area on the back of the solar cell. Therefore, the back encapsulation system must abandon the white encapsulation film and white backsheet, instead using a highly transparent encapsulation film and transparent backsheet. While this adjustment achieves back-side light transmission, it also directly results in the loss of the reflection gain from the white material in the gaps between solar cells and between strings. Light incident on the front of the cells into these gaps cannot be reflected back to the front cells and can only penetrate the back encapsulation layer and be lost, causing a significant drop in front-side power and substantially weakening its overall power generation advantages.

[0005] To address these issues, engineers, after years of research and development, proposed a grid-like back reflective layer solution. This involves setting a localized reflective structure on the back encapsulation layer of a bifacial photovoltaic module, creating highly reflective areas only near the gaps between cells and strings to simulate the gap light reflection effect of a single-sided photovoltaic module, thus supplementing the front power. Simultaneously, a perforated design allows most of the back surface to remain transparent, ensuring back-side power generation. The design aims to achieve a balance between "front-side gain" and "back-side light transmission." However, in actual mass production, limitations in the lamination process and dimensional accuracy control of photovoltaic modules still result in low production yields and high manufacturing costs.

[0006] On the one hand, if production is carried out strictly according to the ideal design where the size of the back reflective layer and the gap size are completely consistent, the encapsulation layers are prone to flow displacement during the lamination process due to differences in thermal shrinkage rates, or alignment deviations may occur in the initial layout, resulting in some gap areas not being covered by the back reflective layer. These uncovered areas will directly expose the transparent encapsulation layer, and incident light from the front cannot be reflected and will pass through directly, forming a light leakage phenomenon visible on the front of the module. Such an anomaly will be judged as a defective module.

[0007] On the other hand, to avoid the aforementioned light leakage phenomenon, existing processes generally adopt a compromise solution of excessively increasing the width of the back reflective layer. That is, the width of the back reflective layer is set to be much larger than the gap width, and sufficient displacement margin is reserved to ensure that the gap is completely covered. However, this solution causes the back reflective layer to extend beyond the gap area, blocking a large area of ​​the effective light-receiving area on the back of the solar cell. Moreover, the low light transmittance of the back reflective layer will hinder the light from the back of the cell from entering the back, directly resulting in a significant decrease in the bifaciality of the module (the ratio of power generation on the back to the power generation on the front), which violates the original design intention of efficient bifacial power generation of bifacial photovoltaic modules.

[0008] Therefore, how to design a bifacial photovoltaic module that ensures power generation on the front side while avoiding light leakage, maintains a high bifaciality, improves production yield, and reduces manufacturing costs has become an urgent problem for those skilled in the art. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a bifacial photovoltaic module and its manufacturing method, which ensures the power generation of the front side while avoiding light leakage, maintains a high bifaciality, improves production yield, and reduces manufacturing costs.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a bifacial photovoltaic module, comprising at least a front encapsulation plate, a front transparent film, a cell layer, a back transparent film, and a back encapsulation plate stacked together, wherein a reflective layer is further disposed between the cell layer and the back encapsulation plate;

[0012] The reflective layer includes at least a first region and a second region, and the battery cell layer includes a plurality of interconnected battery strings, wherein the battery strings are composed of a plurality of battery cells connected in series.

[0013] The second region is a projection area on the reflective layer of at least a portion of the edge region of the battery cell covered area, and the first region is a projection area on the reflective layer of at least a portion of the non-battery cell covered area;

[0014] The front visible light reflectance of the first region is higher than that of the second region, and the back visible light transmittance of the second region is higher than that of the first region.

[0015] In some embodiments, the reflective layer is located between the battery cell layer and the back transparent film.

[0016] In some embodiments, the reflective layer is located between the back transparent film and the back encapsulation plate.

[0017] In some embodiments, the front visible light reflectance of the first region is ≥70%.

[0018] In some embodiments, the front visible light reflectance of the first region is 5% or more higher than the front visible light reflectance of the second region.

[0019] In some embodiments, the front visible light reflectance of the first region is 15% or more higher than the front visible light reflectance of the second region.

[0020] In some embodiments, the front visible light reflectance of the first region is 30% or more higher than the front visible light reflectance of the second region.

[0021] In some embodiments, the visible light transmittance of the back side of the second region is 20% or more higher than that of the back side of the first region.

[0022] In some embodiments, the visible light transmittance of the back side of the second region is 30% or more higher than that of the back side of the first region.

[0023] In some embodiments, the visible light transmittance of the back side of the second region is 45% or more higher than that of the back side of the first region.

[0024] In some embodiments, the reflective layer is made of at least white metal oxide particles.

[0025] In some embodiments, the white metal oxide particles include at least titanium dioxide particles.

[0026] In some embodiments, the average particle size of the titanium dioxide particles is 200nm-400nm.

[0027] In some embodiments, the first region has a gap width of b between two adjacent battery strings in the plurality of battery strings included in the battery cell layer along the first direction, and the gap width of a between two adjacent battery strings in the plurality of battery strings included in the battery cell layer along the first direction is a, b≥0.5a, and the width of the second region in the first direction is c, then b+c≥a+1mm.

[0028] In some embodiments, the gap width between two adjacent cells in the same battery string along the second direction in the first region is b, the gap width between two adjacent cells in the same battery string along the second direction is a, b≥0.5a, and the width of the second region in the second direction is c, then b+c≥a+1mm is satisfied.

[0029] In some embodiments, b ≤ a + 3 mm.

[0030] In some embodiments, b ≥ 0.8a and b ≤ a + 3 mm.

[0031] In some embodiments, b+c≥a+3mm.

[0032] In some embodiments, the reflective layer further includes a third region, and the third region is disposed in the projection area of ​​the coverage area of ​​the plurality of battery cells on the reflective layer.

[0033] In some embodiments, the reflective layer disposed in the third region is at least partially perforated.

[0034] In some embodiments, the width of the second region along the first or second direction is 0.3mm-4mm.

[0035] In a second aspect, the present invention provides a method for preparing a bifacial photovoltaic module as described in the first aspect, comprising at least the following steps:

[0036] (1) A front transparent film and a back transparent film are sequentially applied to both sides of the battery cell layer;

[0037] (2) A front encapsulation plate is provided on the surface of the front transparent film, and then a reflective layer is provided on the surface of the back transparent film;

[0038] (3) A back-side encapsulation plate is provided on the surface of the reflective layer to obtain the bifacial photovoltaic module.

[0039] Thirdly, the present invention provides a method for preparing a bifacial photovoltaic module as described in the first aspect, comprising at least the following steps:

[0040] (1) A transparent adhesive film and a reflective layer are sequentially disposed on both sides of the battery cell layer;

[0041] (2) A front encapsulation plate is provided on the surface of the front transparent film, and then a back transparent film is provided on the surface of the reflective layer;

[0042] (3) A back-side encapsulation plate is provided on the surface of the back transparent film to obtain the double-sided photovoltaic module.

[0043] Fourthly, the present invention provides a photovoltaic system including a bifacial photovoltaic module as described in the first aspect.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] This invention adds a regionally designed reflective layer to a bifacial photovoltaic module. A first region with high reflectivity on the front side handles the main gap light reflection, efficiently reflecting incident light from the front back to the front of the cell to supplement photogenerated carriers and ensure front-side power generation. A second region with high transmittance on the back side addresses the problem of insufficient offset margin; even with slight displacement of the reflective layer, it will not block the effective light-receiving area on the back of the cell. By separately controlling the visible light reflectivity on the front side and the visible light transmittance on the back side of each region, front-side power generation is effectively guaranteed while light leakage is avoided, maintaining a high bifaciality. Attached Figure Description

[0046] Figure 1 This is a schematic diagram showing the positions of various regions of the reflective layer in a bifacial photovoltaic module provided in an embodiment of the present invention.

[0047] Figure 2 This is a schematic diagram of a bifacial photovoltaic module structure provided in an embodiment of the present invention.

[0048] Figure 3 This is a schematic diagram of a bifacial photovoltaic module structure provided in an embodiment of the present invention.

[0049] The components are: 1-Front endplate; 2-Front transparent film; 3-Battery cell layer; 4-Back transparent film; 5-Back endplate; 6-Reflective layer. To demonstrate the main structure, Figure 1 Solder strips and grid lines are omitted. Figure 2 and Figure 3 The grid lines are omitted. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0051] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0053] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0054] In this invention, terms such as "preferred," "better," and "best" are merely descriptions of more effective implementation methods or embodiments, and should be understood not to limit the scope of protection of this invention. In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions comprised of the listed features and open-ended technical solutions that include the listed features. In this invention, numerical ranges are involved; unless otherwise specified, they include the two endpoints of the numerical range.

[0055] In the description of this specification, the references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] like Figure 2 and Figure 3As shown, the present invention provides a bifacial photovoltaic module, which includes at least a front encapsulation plate 1, a front transparent film 2, a cell layer 3, a back transparent film 4 and a back encapsulation plate 5 stacked together, and a reflective layer 6 is also provided between the cell layer 3 and the back encapsulation plate 5.

[0057] The reflective layer 6 includes at least a first region and a second region (see Figure 1 The 3rd layer of the solar cells includes several interconnected battery strings, each consisting of several solar cells connected in series (see [link to relevant documentation]). Figure 2 or Figure 3 );

[0058] The second region is defined as the projection area of ​​at least a portion of the edge region of the battery cell covered area onto the reflective layer 6, and the first region is defined as the projection area of ​​at least a portion of the non-battery cell covered area onto the reflective layer 6 (see...). Figure 1 );

[0059] The front visible light reflectance of the first region is higher than that of the second region, while the back visible light transmittance of the second region is higher than that of the first region.

[0060] This invention adds a regionally designed reflective layer 6 to a bifacial photovoltaic module. A first region with high reflectivity on the front side handles the main gap light reflection, efficiently reflecting incident light from the front side back to the front of the cell to supplement photogenerated carriers and ensure front-side power generation. A second region with high transmittance on the back side addresses the problem of insufficient offset margin; even with slight displacement of the reflective layer 6, it will not block the effective light-receiving area on the back of the cell. By separately controlling the visible light reflectivity on the front side and the visible light transmittance on the back side of each region, front-side power generation is effectively guaranteed while light leakage is avoided, maintaining a high bifaciality.

[0061] In some embodiments, the front encapsulation plate 1 and the back encapsulation plate 5 are made of high-transmittance glass to improve light transmittance and protect the photovoltaic module; the front transparent film 2 and the back transparent film 4 are made of EVA (ethylene-vinyl acetate) or POE (polyolefin elastomer) film to bond, insulate and protect the battery cells.

[0062] In some embodiments, the reflective layer 6 is located between the battery cell layer 3 and the back transparent film 4 (see...). Figure 2 ).

[0063] The aforementioned layering method brings the reflective layer 6 closer to the solar cell layer 3. The highly reflective light from the first region can be directly reflected back to the front of the solar cell, reducing light propagation loss within the encapsulating film. This allows for more efficient supplementation of front-side power generation. Furthermore, this position, being in the middle layer within the module, ensures tighter bonding between encapsulation layers during lamination, making the positioning accuracy of the reflective layer 6 easier to control. This significantly reduces displacement deviations caused by heat shrinkage, further minimizing the risk of light leakage. Simultaneously, the transparent film 4 on the back provides protective coverage for the reflective layer 6, preventing direct friction with the back encapsulation plate 5 or exposure to external environmental influences, thereby enhancing the stability of the reflective layer 6.

[0064] In some embodiments, the reflective layer 6 is located between the back transparent adhesive film 4 and the back encapsulation plate 5 (see...). Figure 3 ).

[0065] The above-mentioned stacking method will not interfere with the bonding process between the battery cell layer 3 and the back transparent adhesive film 4. The positioning accuracy requirements for battery strings / cells are lower during layout and lamination, making it more suitable for mass production processes. It also avoids direct contact between the reflective layer 6 material and the battery cell layer 3, preventing adverse effects on the bonding performance between the adhesive film and the battery cells, thereby ensuring the structural stability of the module.

[0066] In some embodiments, the front visible light reflectance of the first region is ≥70%, for example, it can be 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88% or 90%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0067] This invention limits the visible light reflectivity of the first region to above 70%, which can fully reflect the incident light from the front of the non-cell-covered area, reduce light penetration and loss, and reflect more light back to the front of the cell to supplement the generation of photogenerated carriers, thereby significantly improving the front power generation of the photovoltaic module.

[0068] In some embodiments, the front visible light reflectance of the first region is 5% or more higher than that of the second region, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. Preferably, the front visible light reflectance of the first region is 15% or more higher than that of the second region. More preferably, the front visible light reflectance of the first region is 30% or more higher than that of the second region.

[0069] In some embodiments, the visible light transmittance of the back surface of the second region is 20% or more higher than that of the first region, for example, it can be 20%, 25%, 30%, 35%, 40%, 45%, or 50%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. Preferably, the visible light transmittance of the back surface of the second region is 30% or more higher than that of the first region. More preferably, the visible light transmittance of the back surface of the second region is 45% or more higher than that of the first region.

[0070] In some embodiments, the reflective layer 6 is made of at least white metal oxide particles.

[0071] In some embodiments, the white metal oxide particles include at least titanium dioxide particles.

[0072] In some embodiments, the average particle size of the titanium dioxide particles is 200nm-400nm, for example, it can be 200nm, 220nm, 240nm, 260nm, 280nm, 300nm, 320nm, 340nm, 360nm, 380nm or 400nm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0073] In some embodiments, the first region has a gap width of b between two adjacent battery strings in the battery cell layer 3 along the first direction, and the gap width of a between two adjacent battery strings in the battery cell layer 3 along the first direction is a, where b ≥ 0.5a. The second region has a width of c in the first direction, which satisfies the condition: b + c ≥ a + 1 mm.

[0074] In some embodiments, the gap width between two adjacent cells in the same battery string along the second direction in the first region is b, the gap width between two adjacent cells in the same battery string along the second direction is a, b≥0.5a, and the width of the second region in the second direction is c, then b+c≥a+1mm is satisfied.

[0075] In some embodiments, a ranges from 0.1mm to 6mm, for example, 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, or 6mm; b ranges from 0.08mm to 2mm, for example, 0.08mm, 0.1mm, 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, or 2mm; and c ranges from 0.3mm to 15mm, for example, 0.3mm, 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, or 15mm, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0076] In some embodiments, b ≤ a + 3 mm.

[0077] In some embodiments, b ≥ 0.8a and b ≤ a + 3 mm.

[0078] In some embodiments, b+c≥a+3mm.

[0079] This invention, through a size design of b+c≥a+1mm (preferably b+c≥a+3mm), reserves sufficient displacement margin, effectively avoiding the problem of uncovered gap areas caused by heat shrinkage and layout deviation in the lamination process, completely eliminating light leakage defects, and significantly improving production yield.

[0080] In some embodiments, the reflective layer 6 further includes a third region, which is disposed in the projection area of ​​the coverage area of ​​the plurality of battery cells on the reflective layer 6.

[0081] In some embodiments, the reflective layer 6 disposed in the third region is at least partially perforated. This perforation design ensures that the effective light-receiving areas on the front and back of the solar cell are not blocked, thus not interfering with the power generation function of the solar cell and maintaining the high bifaciality of the photovoltaic module.

[0082] In addition, the non-perforated parts can reflect light that is not fully absorbed by the surface of the solar cell or light scattered from the edges, returning it to the power generation area of ​​the solar cell to supplement the generation of photogenerated carriers and further improve the power generation of the module on the front side.

[0083] In short, the third region complements the first and second regions, ensuring the power generation on the front side while avoiding light leakage, and optimizing the use of light in the area covered by the battery cells without increasing the complexity of the process, making it particularly suitable for mass production needs.

[0084] In some embodiments, the width of the second region along the first or second direction is 0.3mm-4mm, for example, it can be 0.3mm, 0.4mm, 0.6mm, 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm or 4mm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0085] This invention also provides a method for preparing a bifacial photovoltaic module, comprising at least the following steps:

[0086] (1) A front transparent film 2 and a back transparent film 4 are sequentially disposed on both sides of the battery cell layer 3;

[0087] (2) A front encapsulation plate 1 is set on the surface of the front transparent film 2, and then a reflective layer 6 is set on the surface of the back transparent film 4;

[0088] (3) A back-side encapsulation plate 5 is set on the surface of the reflective layer 6 to obtain a double-sided photovoltaic module.

[0089] The above preparation method is used to prepare a bifacial photovoltaic module with the reflective layer 6 located between the back transparent film 4 and the back encapsulation plate 5.

[0090] Alternatively, it may include at least the following steps:

[0091] (1) A front transparent adhesive film 2 and a reflective layer 6 are sequentially disposed on both sides of the battery cell layer 3;

[0092] (2) A front encapsulation plate 1 is set on the surface of the front transparent film 2, and then a back transparent film 4 is set on the surface of the reflective layer 6;

[0093] (3) A back-side encapsulation plate 5 is set on the surface of the back transparent film 4 to obtain a double-sided photovoltaic module.

[0094] The above preparation method is used to prepare a bifacial photovoltaic module in which the reflective layer 6 is located between the battery cell layer 3 and the back transparent film 4.

[0095] The present invention also provides a photovoltaic system, including a bifacial photovoltaic module.

[0096] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0097] Example 1

[0098] This embodiment provides a bifacial photovoltaic module, such as Figure 2 As shown, a bifacial photovoltaic module includes at least a front encapsulation plate 1, a front transparent film 2, a cell layer 3, a back transparent film 4, and a back encapsulation plate 5 stacked together. A reflective layer 6 is also provided between the cell layer 3 and the back transparent film 4.

[0099] like Figure 1 As shown, the reflective layer 6 includes a first region, a second region, and a third region; wherein, the first region is disposed in the projection area of ​​at least a portion of the non-battery cell covered area on the reflective layer 6, the second region is disposed in the projection area of ​​at least a portion of the edge area of ​​the battery cell covered area on the reflective layer 6, and the third region is disposed in the projection area of ​​the battery cell covered area on the reflective layer 6, and the reflective layer 6 disposed in the third region is at least partially hollowed out.

[0100] In this embodiment, the front visible light reflectance of the first region is higher than that of the second region, and the back visible light transmittance of the second region is higher than that of the first region. Specifically, the front visible light reflectance of the first region is ≥70%, and the front visible light reflectance of the first region is 5% or more higher than that of the second region, and the back visible light transmittance of the second region is 20% or more higher than that of the first region; the reflective layer 6 is made of at least titanium dioxide particles with an average particle size of 200nm-400nm.

[0101] like Figure 2 As shown, the battery cell layer 3 includes several interconnected battery strings, each battery string being composed of several battery cells connected in series. Figure 1 As shown, in the first region, the gap width between two adjacent battery strings along the first direction in the battery cell layer 3 is b (ranging from 0.08mm to 2mm), and the gap width between two adjacent battery strings along the first direction in the battery cell layer 3 is a (ranging from 0.1mm to 6mm), and b ≥ 0.5a. The width of the second region in the first direction is c (ranging from 0.3mm to 15mm), which satisfies: b + c ≥ a + 1mm, and b ≤ a + 3mm.

[0102] Example 2

[0103] This embodiment provides a bifacial photovoltaic module, such as Figure 3 As shown, a bifacial photovoltaic module includes at least a front encapsulation plate 1, a front transparent film 2, a cell layer 3, a back transparent film 4, and a back encapsulation plate 5 stacked together, with a reflective layer 6 disposed between the back transparent film 4 and the back encapsulation plate 5.

[0104] like Figure 1 As shown, the reflective layer 6 includes a first region, a second region, and a third region; wherein, the first region is disposed in the projection area of ​​at least a portion of the non-battery cell covered area on the reflective layer 6, the second region is disposed in the projection area of ​​at least a portion of the edge area of ​​the battery cell covered area on the reflective layer 6, and the third region is disposed in the projection area of ​​the battery cell covered area on the reflective layer 6, and the reflective layer 6 disposed in the third region is at least partially hollowed out.

[0105] In this embodiment, the front visible light reflectance of the first region is higher than that of the second region, and the back visible light transmittance of the second region is higher than that of the first region. Specifically, the front visible light reflectance of the first region is ≥70%, and the front visible light reflectance of the first region is 15% or more higher than that of the second region, while the back visible light transmittance of the second region is 30% or more higher than that of the first region; the reflective layer 6 is made of at least titanium dioxide particles with an average particle size of 200nm-400nm.

[0106] like Figure 2 As shown, the battery cell layer 3 includes several interconnected battery strings, each battery string being composed of several battery cells connected in series. Figure 1 As shown, in the first region, the gap width between two adjacent battery strings along the first direction in the battery cell layer 3 is b (ranging from 0.08mm to 2mm), and the gap width between two adjacent battery strings along the first direction in the battery cell layer 3 is a (ranging from 0.1mm to 6mm), b ≥ 0.8a. The width of the second region in the first direction is c (ranging from 0.3mm to 15mm). Then, the following conditions are met: b + c ≥ a + 3mm, and b ≤ a + 3mm.

[0107] Example 3

[0108] This embodiment provides a bifacial photovoltaic module. Except that the gap width between two adjacent cells in the same cell string along the second direction in the first region is b (ranging from 0.08mm to 2mm), and the gap width between two adjacent cells in the same cell string along the second direction is a (ranging from 0.1mm to 6mm), b ≥ 0.5a, and the width of the second region in the second direction is c (ranging from 0.3mm to 15mm), then the following conditions are met: b + c ≥ a + 1mm, and b ≤ a + 3mm. The remaining structure and conditions are the same as in Embodiment 1, and will not be repeated here.

[0109] Example 4

[0110] This embodiment provides a bifacial photovoltaic module. Except that the gap width between two adjacent cells in the same cell string along the second direction in the first region is b (ranging from 0.08mm to 2mm), and the gap width between two adjacent cells in the same cell string along the second direction is a (ranging from 0.1mm to 6mm), b≥0.8a, and the width of the second region in the second direction is c (ranging from 0.3mm to 15mm), then the following conditions are met: b+c≥a+3mm and b≤a+3mm. The remaining structure and conditions are the same as in Embodiment 2, and will not be repeated here.

[0111] Example 5

[0112] This embodiment provides a bifacial photovoltaic module. Except for retaining only the first and second regions, the rest of the structure and conditions are the same as those in Embodiment 1, and will not be described again here.

[0113] Example 6

[0114] This embodiment provides a bifacial photovoltaic module. Except for retaining only the first and second regions, the rest of the structure and conditions are the same as those in Embodiment 2, and will not be described again here.

[0115] Example 7

[0116] This embodiment provides a method for preparing a bifacial photovoltaic module, which includes at least the following steps:

[0117] (1) A front transparent film 2 and a back transparent film 4 are sequentially disposed on both sides of the battery cell layer 3;

[0118] (2) A front encapsulation plate 1 is set on the surface of the front transparent film 2, and then a reflective layer 6 is set on the surface of the back transparent film 4;

[0119] (3) A back-side encapsulation plate 5 is set on the surface of the reflective layer 6 to obtain a double-sided photovoltaic module.

[0120] Example 8

[0121] This embodiment provides a method for preparing a bifacial photovoltaic module, which includes at least the following steps:

[0122] (1) A front transparent adhesive film 2 and a reflective layer 6 are sequentially disposed on both sides of the battery cell layer 3;

[0123] (2) A front encapsulation plate 1 is set on the surface of the front transparent film 2, and then a back transparent film 4 is set on the surface of the reflective layer 6;

[0124] (3) A back-side encapsulation plate 5 is set on the surface of the back transparent film 4 to obtain a double-sided photovoltaic module.

[0125] Example 9

[0126] This embodiment provides a photovoltaic system, including a bifacial photovoltaic module as described in any one of Embodiments 1 to 8.

[0127] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0128] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A bifacial photovoltaic module, comprising at least a front encapsulation plate, a front transparent film, a layer of solar cells, a back transparent film, and a back encapsulation plate stacked together, characterized in that, A reflective layer is also provided between the battery cell layer and the back encapsulation plate; The reflective layer is located between the battery cell layer and the back transparent film, or the reflective layer is located between the back transparent film and the back encapsulation plate; The reflective layer includes at least a first region and a second region, and the battery cell layer includes a plurality of interconnected battery strings, wherein the battery strings are composed of a plurality of battery cells connected in series. The second region is a projection area on the reflective layer of at least a portion of the edge region of the battery cell covered area, and the first region is a projection area on the reflective layer of at least a portion of the non-battery cell covered area; The front visible light reflectance of the first region is higher than that of the second region, and the back visible light transmittance of the second region is higher than that of the first region.

2. The bifacial photovoltaic module according to claim 1, characterized in that, The frontal visible light reflectance of the first region is ≥70%.

3. The bifacial photovoltaic module according to claim 2, characterized in that, The front visible light reflectance of the first region is 5% or more higher than that of the second region.

4. The bifacial photovoltaic module according to claim 3, characterized in that, The front visible light reflectance of the first region is 15% or more higher than that of the second region.

5. The bifacial photovoltaic module according to claim 4, characterized in that, The front visible light reflectance of the first region is 30% or more higher than that of the second region.

6. The bifacial photovoltaic module according to claim 1, characterized in that, The visible light transmittance of the back side of the second region is 20% or more higher than that of the back side of the first region.

7. The bifacial photovoltaic module according to claim 6, characterized in that, The visible light transmittance of the back side of the second region is 30% or more higher than that of the back side of the first region.

8. The bifacial photovoltaic module according to claim 7, characterized in that, The visible light transmittance of the back side of the second region is 45% or more higher than that of the back side of the first region.

9. The bifacial photovoltaic module according to claim 1, characterized in that, The reflective layer is made of white metal oxide particles.

10. The bifacial photovoltaic module according to claim 9, characterized in that, The white metal oxide particles include titanium dioxide particles.

11. The bifacial photovoltaic module according to claim 10, characterized in that, The average particle size of the titanium dioxide particles is 200nm-400nm.

12. The bifacial photovoltaic module according to claim 1, characterized in that, The first region has a gap width of b between two adjacent battery strings in the battery cell layer along the first direction, and the gap width of a between two adjacent battery strings in the battery cell layer along the first direction is a, where b ≥ 0.5a. The second region has a width of c in the first direction, which satisfies: b + c ≥ a + 1 mm.

13. The bifacial photovoltaic module according to claim 1, characterized in that, The first region has a gap width of b between two adjacent cells in the same battery string along the second direction, and a between two adjacent cells in the same battery string along the second direction, where b ≥ 0.5a. The second region has a width of c in the second direction, which satisfies the condition: b + c ≥ a + 1 mm.

14. The bifacial photovoltaic module according to claim 12 or 13, characterized in that, b≤a+3mm.

15. The bifacial photovoltaic module according to claim 12 or 13, characterized in that, b≥0.8a, and b≤a+3mm.

16. The bifacial photovoltaic module according to claim 12 or 13, characterized in that, b+c≥a+3mm.

17. The bifacial photovoltaic module according to claim 1, characterized in that, The reflective layer further includes a third region, which is disposed in the projection area of ​​the coverage area of ​​the plurality of battery cells on the reflective layer.

18. The bifacial photovoltaic module according to claim 17, characterized in that, The reflective layer located in the third region is at least partially perforated.

19. The bifacial photovoltaic module according to claim 12 or 13, characterized in that, The width of the second region along the first or second direction is 0.3mm-4mm.

20. A method for preparing a bifacial photovoltaic module as described in any one of claims 1-19, characterized in that, The preparation method includes at least the following steps: (1) A front transparent film and a back transparent film are sequentially applied to both sides of the battery cell layer; (2) A front encapsulation plate is provided on the surface of the front transparent film, and then a reflective layer is provided on the surface of the back transparent film; (3) A back-side encapsulation plate is disposed on the surface of the reflective layer to obtain the bifacial photovoltaic module; Alternatively, the preparation method may include at least the following steps: (1) A transparent adhesive film and a reflective layer are sequentially disposed on both sides of the battery cell layer; (2) A front encapsulation plate is provided on the surface of the front transparent film, and then a back transparent film is provided on the surface of the reflective layer; (3) A back-side encapsulation plate is provided on the surface of the back transparent film to obtain the double-sided photovoltaic module.

21. A photovoltaic system, characterized in that, Including the bifacial photovoltaic module as described in any one of claims 1-19.

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