Encapsulation layer and photovoltaic module

Abstract

The utility model relates to the photovoltaic technology field, and provides a packaging layer and a photovoltaic assembly, the packaging layer comprises a first adhesive film layer and a second adhesive film layer which are laminated, and the lowest vulcanization torque value of the first adhesive film layer is higher than the lowest vulcanization torque value of the second adhesive film layer. According to the utility model, the first adhesive film layer and the second adhesive film layer are arranged in the packaging layer, the lowest vulcanization torque value of the first adhesive film layer is higher than that of the second adhesive film layer, and the first adhesive film layer cannot permeate between the welding strip and the grid line of the photovoltaic module due to poor fluidity, and can prevent the second adhesive film layer from permeating; alloy contact between the welding strip and the grid line is effectively ensured, and the preparation yield of products is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, in particular to a packaging layer and a photovoltaic component. Background Art

[0002] With the development of photovoltaic module technology, busbar-free (0BB, 0 Busbar) packaging technology has become an important technology for photovoltaic modules. 0BB packaging technology does not print busbars in the preparation of solar cells, but only prints fine grid lines. By optimizing the width and spacing of fine grid lines, copper welding strips are used to replace busbars and bond with fine grid lines to collect current, effectively reducing the amount of silver paste and the cost of photovoltaic modules.

[0003] However, the 0BB packaging technology uses an adhesive solder tape structure. Before lamination, the solder tape and the battery grid line do not form an alloy, and there is a gap between the solder tape and the battery grid line. As a result, when the packaging film melts during lamination, it is easy to penetrate into the position between the solder tape and the grid line, resulting in no alloy being formed between the solder tape and the battery grid line, causing serious false connection after lamination, which has a negative impact on both component power and product reliability. Utility Model Content

[0004] Based on this, an embodiment of the utility model provides a packaging layer and a photovoltaic module that solve the problem of virtual connection between welding strips and grid lines.

[0005] In a first aspect, the utility model provides a packaging layer, which includes a first adhesive film layer and a second adhesive film layer stacked together, wherein the minimum vulcanization torque value of the first adhesive film layer is higher than the minimum vulcanization torque value of the second adhesive film layer.

[0006] In some embodiments, the minimum vulcanization torque value of the first adhesive film layer is 0.4 N·m (kgf·cm) to 0.6 N·m (kgf·cm).

[0007] In some embodiments, the minimum vulcanization torque value of the second adhesive film layer is 0.1 N·m (kgf·cm) to 0.2 N·m (kgf·cm).

[0008] In some embodiments, the thickness of the first adhesive film layer is 0.05 mm to 0.15 mm.

[0009] In some embodiments, the thickness of the second adhesive film layer is 0.3 mm to 1 mm.

[0010] In some embodiments, the ratio of the thickness of the first adhesive film layer to the thickness of the second adhesive film layer is 1:(2-5).

[0011] In some embodiments, a plurality of holes are formed on the first adhesive film layer, the holes penetrate the first adhesive film layer along the thickness direction, and the second adhesive film layer at least partially extends into the holes.

[0012] In some embodiments, the diameter of the hole is 2 mm to 7 mm.

[0013] In some embodiments, the total area of ​​the holes accounts for 5% to 25% of the area of ​​the first adhesive film layer.

[0014] In a second aspect, the utility model provides a photovoltaic module, the photovoltaic module comprising a battery string and an encapsulation layer as described in the first aspect;

[0015] The battery string includes a plurality of battery cells and welding strips, and the welding strips are electrically connected to the grid lines on the battery cells;

[0016] The encapsulation layer is arranged on at least one side surface of the battery string and covers the welding strip. The first adhesive film layer and the second adhesive film layer in the encapsulation layer are stacked in sequence in a direction away from the surface of the battery string. The first adhesive film layer is used to prevent the second adhesive film layer from penetrating between the welding strip and the grid line after melting.

[0017] In some embodiments, holes are provided in the first adhesive film layer at positions between adjacent welding strips in the plane direction where the battery string is located.

[0018] In some embodiments, the straight-line distance between the hole and the welding strip in the plane direction where the battery string is located is ≥2.5 mm.

[0019] In some embodiments, the photovoltaic module further includes a panel layer, and the panel layer is disposed on a surface of the packaging layer on a side away from the solar cell.

[0020] Compared with the traditional technology, the utility model has at least the following beneficial effects:

[0021] The utility model arranges a first adhesive film layer and a second adhesive film layer in the packaging layer, wherein the minimum vulcanization torque value of the first adhesive film layer is higher than that of the second adhesive film layer. During the lamination process, the adhesive film fluidity of the first adhesive film layer is worse than that of the second adhesive film layer. Not only will the first adhesive film layer not penetrate between the welding strip and the grid line due to the poor fluidity, but it can also prevent the second adhesive film layer from penetrating, thereby effectively ensuring the alloy contact between the welding strip and the grid line and improving the preparation yield of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of a photovoltaic module including an encapsulation layer provided in one embodiment of the utility model;

[0023] Figure 2This is a schematic diagram of a structure with holes in a packaging layer provided in one embodiment of the utility model;

[0024] Figure 3 This is a schematic diagram of the structure of a battery string provided in one embodiment of the utility model;

[0025] Figure 4 It is a schematic diagram of the structure of a battery cell and a welding strip provided in one embodiment of the utility model.

[0026] Among them, 100 - battery string; 110 - battery cell; 111 - grid line; 120 - solder strip; 200 - packaging layer; 210 - first adhesive film layer; 211 - hole; 220 - second adhesive film layer; 300 - panel layer. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings, embodiments and examples. These embodiments and examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. The purpose of providing these embodiments and examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive. It should also be understood that the present invention can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various changes or modifications without violating the connotation of the present invention, and the equivalent forms obtained also fall within the scope of protection of the present invention. In addition, in the description below, a large number of specific details are given in order to provide a more comprehensive understanding of the present invention. It should be understood that the present invention can be implemented without one or more of these details.

[0028] It should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention 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 invention.

[0029] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", "fixed" and "set" 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. For ordinary technicians in this field, the meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "option" is independent.

[0031] In the present utility model, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0032] In the present invention, the terms "first", "second", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0033] All documents mentioned in the present utility model are cited as references in the present utility model, just as each document is cited as a reference separately. Unless they conflict with the utility model purpose and / or technical solution of the present utility model, the cited documents involved in the present utility model are cited with all contents and all purposes. When the present utility model involves cited documents, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the present utility model involves cited documents, the examples and preferred methods of the cited relevant technical features can also be incorporated into the present utility model as references, but are limited to the ability to implement the present utility model. It should be understood that when the cited content conflicts with the description in the present utility model, the present utility model shall prevail or be modified adaptively according to the description of the present utility model.

[0034] In the traditional technology, the main grid-free packaging technology uses glue distributed in dots to pre-fix the welding strip on the battery cell. After the glue is cured, the welding strip is not completely attached to the battery cell in all places, and there is a gap between the welding strip and the grid line. In the subsequent lamination process, the packaging film (a material with high fluidity and non-conductive) may melt and penetrate between the battery cell and the welding strip to form an insulating layer, causing the problem of virtual connection of the welding strip. In the utility model, by setting the packaging layer into a two-layer structure, the side close to the battery cell uses a first film layer with poor fluidity, which can prevent the first film layer and the second film layer from penetrating between the battery cell and the welding strip during the lamination process. The first film layer effectively protects the welding stability of the welding strip and avoids the occurrence of problems such as virtual connection.

[0035] The first aspect of the utility model provides a packaging layer, such as Figure 1As shown, the encapsulation layer 200 includes a first adhesive film layer 210 and a second adhesive film layer 220 which are stacked, and the lowest vulcanization torque value of the first adhesive film layer 210 is higher than the lowest vulcanization torque value of the second adhesive film layer 220 .

[0036] The utility model arranges a first adhesive film layer 210 and a second adhesive film layer 220 in the encapsulation layer 200, wherein the minimum vulcanization torque value of the first adhesive film layer 210 is higher than that of the second adhesive film layer 220, that is, the adhesive film fluidity of the first adhesive film layer 210 is worse than that of the second adhesive film layer 220 during the lamination process. Not only will the first adhesive film layer 210 not penetrate between the welding strip and the gate line due to the poor fluidity, but it can also prevent the second adhesive film layer 220 from penetrating.

[0037] It should be noted that the minimum vulcanization torque value in this application refers to the torque value of the lowest point on the vulcanization curve obtained in the vulcanization experiment. The lower this value is, the higher the fluidity of the rubber, and vice versa. Fluidity refers to the spreading and wetting ability of the glue in the film layer during the lamination preparation process of photovoltaic modules. If the minimum vulcanization torque value is small, the film can spread and infiltrate on the battery cell quickly, and it is easy to penetrate the film between the solder strip and the grid line during the lamination process; poor fluidity refers to the slow spreading and wetting speed of the film on the battery cell, that is, it is difficult to penetrate between the solder strip and the grid line during the lamination process.

[0038] In some embodiments, the minimum vulcanization torque value (ML) of the first adhesive film layer 210 is 0.4N·m (kgf·cm) to 0.6N·m (kgf·cm), for example, it may be 0.40N·m (kgf·cm), 0.42N·m (kgf·cm), 0.44N·m (kgf·cm), 0.46N·m (kgf·cm), 0.48N·m (kgf·cm), 0.50N·m (kgf·cm), 0.52N·m (kgf·cm), 0.54N·m (kgf·cm), 0.56N·m (kgf·cm), 0.58N·m (kgf·cm) or 0.60N·m (kgf·cm).

[0039] In some embodiments, the minimum vulcanization torque value (ML) of the second adhesive film layer 220 is 0.1N·m (kgf·cm) to 0.2N·m (kgf·cm), for example, it may be 0.10N·m (kgf·cm), 0.11N·m (kgf·cm), 0.12N·m (kgf·cm), 0.13N·m (kgf·cm), 0.14N·m (kgf·cm), 0.15N·m (kgf·cm), 0.16N·m (kgf·cm), 0.17N·m (kgf·cm), 0.18N·m (kgf·cm), 0.19N·m (kgf·cm) or 0.20N·m (kgf·cm).

[0040] In some embodiments, the thickness of the first adhesive film layer 210 is 0.05 mm to 0.15 mm. For example, the thickness of the first adhesive film layer 210 may be 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.10 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm or 0.15 mm.

[0041] In some embodiments, the thickness of the second film layer 220 is 0.3 mm to 1 mm. For example, the thickness of the second film layer 220 can be 0.30 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm, 0.55 mm, 0.60 mm, 0.65 mm, 0.70 mm, 0.75 mm, 0.80 mm, 0.85 mm, 0.90 mm, 0.95 mm or 1.00 mm.

[0042] In some embodiments, the ratio of the thickness of the first adhesive film layer 210 to the thickness of the second adhesive film layer 220 is 1:(2~5). For example, the ratio of the thickness of the first adhesive film layer 210 to the thickness of the second adhesive film layer 220 can be 1:2.0, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3.0, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4.0, 1:4.2, 1:4.4, 1:4.6, 1:4.8 or 1:5.0.

[0043] In some embodiments, Figure 2 As shown, a plurality of holes 211 are formed on the first adhesive film layer 210, and the holes 211 penetrate the first adhesive film layer 210 along the thickness direction. The second adhesive film layer 220 at least partially extends into the holes 211. The encapsulation layer 200 is disposed on the surface of the battery cell 110, the first adhesive film layer 210 is in contact with the battery cell 110, and the surface of the battery cell 110 is provided with a welding strip 120.

[0044] The utility model opens holes 211 penetrating through the thickness direction on the first adhesive film layer 210, which can not only exhaust the air between the battery cell 110 and the first adhesive film layer 210 through the holes 211, but also when laminating the second adhesive film layer 220, the second adhesive film layer 220 can enter the holes 211 after being partially melted, and after the adhesive film is solidified, the bonding force between the first adhesive film layer 210 and the second adhesive film layer 220 is effectively improved. In addition, part of the second adhesive film layer 220 can penetrate between the first adhesive film layer 210 and the battery cell 110, but will not enter between the welding strip 120 and the grid line. The second adhesive film layer 220 can be partially bonded to the battery cell 110 through the holes 211, thereby improving the bonding force between the encapsulation layer 200 and the battery cell 110 and improving the stability of the device.

[0045] In some embodiments, the diameter of the hole 211 is 2 mm to 7 mm. For example, the diameter of the hole 211 may be 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, or 7.0 mm.

[0046] The utility model controls the diameter of the hole 211 and ensures the amount of glue seepage of the second adhesive film layer 220, which can improve the bonding effect between the first adhesive film layer 210 and the second adhesive film layer 220 and the bonding effect between the encapsulation layer 200 and the battery cell 110; in addition, it prevents the hole 211 from being too large, resulting in excessive glue seepage, thereby preventing the glue seepage of the second adhesive film layer 220 from entering between the welding strip 120 and the gate line.

[0047] In some embodiments, the total area of ​​the holes 211 accounts for 5% to 25% of the area of ​​the first film layer 210 , for example, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23% or 25%.

[0048] The second aspect of the utility model provides a photovoltaic module. Figure 1 As shown, the photovoltaic module includes a battery string 100 and an encapsulation layer 200 as described in the first aspect;

[0049] like Figure 3 As shown, the battery string 100 includes a plurality of battery cells 110 and 120 welding strips, and the welding strips 120 are electrically connected to the grid lines on the battery cells 110;

[0050] The encapsulation layer 200 is arranged on at least one side surface of the battery string 100 and covers the welding strip 120. The first adhesive film layer 210 and the second adhesive film layer 220 in the encapsulation layer 200 are stacked in sequence in a direction away from the surface of the battery string 100. The first adhesive film 210 layer is used to prevent the second adhesive film layer 220 from penetrating between the welding strip 120 and the gate line after melting.

[0051] In some embodiments, Figure 4 As shown, the grid lines 111 of the cell 110 are fine grids arranged side by side. Optionally, the width of the grid lines 111 of the fine grids is 15μm to 60μm, for example, the width of the grid lines 111 can be 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm or 60μm. The spacing between adjacent fine grids is 7mm to 12mm, for example, it can be 7.0mm, 7.5mm, 8.0mm, 8.5mm, 9.0mm, 9.5mm, 10.0mm, 10.5mm, 11.0mm, 11.5mm or 12.0mm.

[0052] In some embodiments, the soldering strip 120 is disposed to cross the gate line 111. Optionally, the soldering strip 120 is disposed perpendicular to the gate line 111.

[0053] In some embodiments, the cell 110 may be at least one of a HJT cell, a TOPcon cell, or a PERC cell.

[0054] In some embodiments, the material of the first adhesive film layer 210 is pre-crosslinked vinyl acetate (EVA) material. It is understandable that pre-crosslinking of vinyl acetate can form a three-dimensional network structure of vinyl acetate, thereby reducing fluidity and increasing viscosity. Optionally, the crosslinking degree of the vinyl acetate material is 40% to 60%, for example, it can be 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58% or 60%. Further optionally, the gram weight of the vinyl acetate material is 50g / m 2 ~150g / m 2 , for example, it can be 50g / m 2 , 60g / m 2 , 70g / m 2 , 80g / m 2 , 90g / m 2 , 100g / m 2 , 110g / m 2 , 120g / m 2 , 130g / m 2 , 140g / m 2 or 150g / m 2 .

[0055] In some embodiments, the bonding strength between the first adhesive film layer 210 and the battery cell 110 is ≥ 20 N / cm 2 .

[0056] In some embodiments, the material of the second adhesive film layer 220 may be vinyl acetate that has not been pre-crosslinked. Optionally, the weight of the vinyl acetate that has not been pre-crosslinked is ≥350 g / m 2 .

[0057] In some embodiments, the first adhesive film layer 210 may be a high light transmittance adhesive film layer or a high cutoff adhesive film layer.

[0058] In some embodiments, the second adhesive film layer 220 may be a high light transmittance adhesive film layer, a high cutoff adhesive film layer, or a light conversion adhesive film layer.

[0059] Among them, the high light transmittance film layer refers to the light transmittance of the sunlight wavelength band of 290nm~380nm ≥70%; the high cut-off film layer refers to the light transmittance of the sunlight wavelength band of 290nm~380nm ≤30%. The light conversion film layer refers to the film layer that can convert ultraviolet light into visible light.

[0060] In some embodiments, the first adhesive film layer 210 and the second adhesive film layer 220 in the encapsulation layer 200 are matched by different properties, and photovoltaic modules with different functions are obtained after encapsulating the battery string 100. For example, the first adhesive film layer 210 uses a high-transmittance adhesive film layer, and the second adhesive film layer 220 also uses a high-transmittance adhesive film layer, which is used for an encapsulation solution with a strong anti-ultraviolet ability of the battery cell 110; the first adhesive film layer 210 uses a high-transmittance adhesive film layer, and the second adhesive film layer 220 uses a high-cutoff adhesive film layer, which is used for an encapsulation solution with a weak anti-ultraviolet ability of the battery cell 110; the first adhesive film layer 210 uses a high-transmittance adhesive film layer, and the second adhesive film layer 220 uses a light conversion adhesive film layer, which is used to maximize the power of the battery cell 110 The packaging scheme is as follows: the first film layer 210 is a high-cutoff film layer, and the second film layer 220 is also a high-cutoff film layer, with double cutoff, which is used in areas where the battery cell 110 has weak UV resistance and strong UV in the use occasion; the first film layer 210 is a high-cutoff film layer, and the second film layer 220 is a light conversion film layer, which converts UV light into visible light, and uses the high-cutoff film layer to cut off the unconverted UV light, effectively ensuring the power of the component and having reliability.

[0061] In some embodiments, a hole 211 is provided at a position of the first adhesive film layer 210 between adjacent welding strips 120 in the plane direction of the battery string 100. Optionally, the hole 211 is centrally provided between two adjacent welding strips 120.

[0062] In some embodiments, the solder strips 120 are arranged side by side on the battery cell 110. Optionally, the distance between two adjacent solder strips 120 is 7 mm to 12 mm, for example, 7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm, 9.5 mm, 10.0 mm, 10.5 mm, 11.0 mm, 11.5 mm or 12.0 mm. Optionally, the spacing between adjacent holes 211 is greater than the distance between two adjacent solder strips 120.

[0063] In some embodiments, the linear distance between the hole 211 and the soldering strip 120 in the plane direction of the battery string 100 is ≥ 2.5 mm. The distance between the hole 211 and the soldering strip 120 in the present invention refers to the linear distance between the edge of the hole 211 closest to the soldering strip 120 and the soldering strip 120 .

[0064] The utility model controls the distance between the hole 211 and the soldering strip 120, thereby preventing the second adhesive film layer 220 from penetrating into between the soldering strip 120 and the gate line 111 after entering the hole 211. If the distance between the hole 211 and the soldering strip 120 is short, there is a risk that the second adhesive film layer 220 will penetrate into between the soldering strip 120 and the gate line 111 during the lamination process.

[0065] In some embodiments, the photovoltaic module further includes a panel layer 300, and the panel layer 300 is disposed on a surface of the encapsulation layer 200 that is away from the solar cell 110. Optionally, the panel layer 300 may be a single-layer structure or a multi-layer structure.

[0066] In some embodiments, the photovoltaic module further includes a back plate. The back plate is disposed on the back side of the cell 110. Optionally, the back side of the cell 110 is provided with an encapsulation layer 200 and a back plate in sequence in a direction away from the cell 110. It should be noted that the back side in the present invention refers to the side facing away from the sunlight. Correspondingly, the front side refers to the side directly exposed to the sunlight.

[0067] In some embodiments, the photovoltaic module further includes a frame. The stacked body formed by the cell 110, the encapsulation layer 200, the panel layer 300, and the back plate is arranged in the frame. The frame is used to improve the mechanical strength of the stacked body.

[0068] In some embodiments, the photovoltaic module further includes a junction box, which is electrically connected to the welding ribbon 120 and is used to protect the battery cell 110 and prevent current short circuit.

[0069] In some embodiments, the first adhesive film layer 210 and the second adhesive film layer 220 in the encapsulation layer 200 may be pre-compounded to form the encapsulation layer 200. Alternatively, the encapsulation layer 200 is formed by sequentially forming the first adhesive film layer 210 and the second adhesive film layer 220 on the battery cell 110. In other words, the first adhesive film layer 210 and the second adhesive film layer 220 may be stacked to form an integral film; or they may be stacked separately as independent film layers.

[0070] In summary, the utility model arranges a first adhesive film layer 210 and a second adhesive film layer 220 in the packaging layer 200, wherein the minimum vulcanization torque value of the first adhesive film layer 210 is higher than that of the second adhesive film layer 220, that is, during the lamination process, the adhesive film fluidity of the first adhesive film layer 210 is worse than that of the second adhesive film layer 220. Not only will the first adhesive film layer 210 not penetrate between the soldering strip 120 and the gate line 111 due to the poor fluidity, but it can also prevent the second adhesive film layer 220 from penetrating, thereby effectively ensuring the alloy contact between the soldering strip 120 and the gate line 111, and improving the preparation yield of the product.

[0071] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above embodiments only express several implementation methods of the utility model, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A packaging layer, characterized in that: The packaging layer (200) comprises a first adhesive film layer (210) and a second adhesive film layer (220) which are stacked, and the minimum vulcanization torque value of the first adhesive film layer (210) is higher than the minimum vulcanization torque value of the second adhesive film layer (220).

2. The encapsulation layer according to claim 1, characterized in that The minimum vulcanization torque value of the first adhesive film layer (210) is 0.4 N·m (kgf·cm) to 0.6 N·m (kgf·cm); and / or, The minimum vulcanization torque value of the second adhesive film layer (220) is 0.1 N·m (kgf·cm) to 0.2 N·m (kgf·cm).

3. The encapsulation layer according to claim 1, characterized in that The thickness of the first adhesive film layer (210) is 0.05 mm to 0.15 mm; and / or, The thickness of the second adhesive film layer (220) is 0.3 mm to 1 mm; and / or, The ratio of the thickness of the first adhesive film layer (210) to the thickness of the second adhesive film layer (220) is 1:(2-5).

4. The encapsulation layer according to any one of claims 1 to 3, characterized in that: The first adhesive film layer (210) is provided with a plurality of holes (211), the holes (211) penetrate the first adhesive film layer (210) along the thickness direction, and the second adhesive film layer (220) at least partially extends into the holes (211).

5. The encapsulation layer according to claim 4, characterized in that The diameter of the hole (211) is 2 mm to 7 mm.

6. The encapsulation layer according to claim 4, characterized in that The total area of ​​the holes (211) accounts for 5% to 25% of the area of ​​the first adhesive film layer (210).

7. A photovoltaic module, characterized in that: The photovoltaic module comprises a battery string (100) and an encapsulation layer (200) according to any one of claims 1 to 6; The battery string (100) comprises a plurality of battery cells (110) and welding strips (120), wherein the welding strips (120) are electrically connected to the grid lines (111) on the battery cells (110); The encapsulation layer (200) is arranged on at least one side surface of the battery string (100) and covers the welding strip (120); the first adhesive film layer (210) and the second adhesive film layer (220) in the encapsulation layer (200) are stacked in sequence in a direction away from the surface of the battery string (100); the first adhesive film layer (210) is used to prevent the second adhesive film layer (220) from penetrating between the welding strip (120) and the gate line (111) after melting.

8. The photovoltaic module according to claim 7, characterized in that: The first adhesive film layer (210) is provided with holes (211) at positions between adjacent welding strips (120) in the plane direction where the battery string (100) is located.

9. The photovoltaic module according to claim 8, characterized in that: The straight-line distance between the hole (211) and the welding strip (120) in the plane direction where the battery string (100) is located is ≥2.5 mm.

10. The photovoltaic module according to any one of claims 7 to 9, characterized in that: The photovoltaic assembly further comprises a panel layer (300), wherein the panel layer (300) is arranged on a surface of a side of the encapsulation layer (200) away from the battery cell (110).

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