Composite structure encapsulation adhesive film, solar cell module

Abstract

The utility model belongs to solar cell module technical field, concretely relates to a kind of composite structure encapsulation adhesive film, comprising: EPE adhesive film layer in central region and POE adhesive film layer around periphery jointly constitute hui character shape plane structure;Wherein, the EPE adhesive film layer is not pre-crosslinking or crosslinking degree <10%, the pre-crosslinking degree range of the POE adhesive film layer is 10~40%;And, the thickness of the POE adhesive film layer is 0.2~0.4mm than the thickness of the EPE adhesive film layer is greater;The composite structure encapsulation adhesive film on the basis of existing hui character shape composite encapsulation adhesive film is directed to the feature that welding stress is more easily conducted to cell edge in main gridless technology, and the POE adhesive film layer of edge portion is changed to pre-crosslinking POE with higher initial strength and modulus, so that it can better support cell and reduce hidden crack in welding process, while the interval of edge thickening can accurately compensate the shrinkage difference of dissimilar materials in laminating process, avoid producing arc or wave-shaped defects, ensure module flatness.The utility model also discloses solar cell module.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar cell modules, and specifically relates to a composite structure encapsulation adhesive film and a solar cell module. Background Art

[0002] As a clean energy device, the core part of a solar cell module is composed of cell sheets and encapsulation materials. The encapsulation adhesive film layer plays a key protective role for cell sheets, and directly determines the output power, service life and long-term reliability of the module. At present, mainstream encapsulation adhesive film materials include EVA, POE, EPE, etc.

[0003] As an emerging co-extruded composite adhesive film, the performance of EPE adhesive film is between that of EVA and POE. It not only retains the good processability and low-cost characteristics of EVA, but also introduces some advantages of POE. It has better water blocking performance than EVA and a certain PID resistance capability, and its cost is significantly lower than that of pure POE adhesive films. However, the current EPE adhesive film still has a gap compared with pure POE adhesive film in terms of the absolute reliability of PID resistance, especially in harsh environments.

[0004] Existing patent CN222374621U: adopts a "loop-shaped" adhesive film layer, with an EVA layer in the central area and a POE layer in the edge area. This structure uses the excellent PID resistance of POE material to strengthen edge protection to a certain extent, and at the same time uses the low-cost advantage of EVA material to control the overall cost, which provides an idea for solving the problems of module edge PID and cost.

[0005] However, with the development of solar cell technology towards advanced processes such as no main grid and thinning, in the prior patent solution, different thermal expansion coefficients and shrinkage rates of the two materials during lamination heating will cause internal stress in the interface area. If this stress cannot be effectively released or compensated, warping will occur, which is difficult to meet the manufacturing requirements of a new generation of high-performance modules.

[0006] Therefore, how to provide an encapsulation adhesive film that overcomes the warping defect of heterogeneous materials in the lamination of the "loop-shaped" adhesive film layer is an urgent technical problem to be solved in the art.

[0007] It should be noted that the above information disclosed in this background section is only for understanding the background of the concept of the present application, and therefore, it is not considered that the above description constitutes information of the prior art. Summary of the Invention

[0008] Embodiments of the present disclosure provide at least one composite structure encapsulation adhesive film and a solar cell module.

[0009] In a first aspect, embodiments of this disclosure provide a composite structure encapsulating film, comprising: an EPE film layer located in the central region and a POE film layer surrounding the periphery, together forming a U-shaped planar structure; wherein the EPE film layer is not pre-crosslinked or has a crosslinking degree of <10%, and the pre-crosslinking degree of the POE film layer ranges from 10% to 40%; and the thickness of the POE film layer is 0.2 to 0.4 mm greater than the thickness of the EPE film layer.

[0010] In one optional embodiment, the width of the POE film layer is 50–70 mm.

[0011] In one optional embodiment, the thickness of the EPE film layer ranges from 0.3 to 0.8 mm.

[0012] In one optional embodiment, the thickness of the POE film layer ranges from 0.5 to 1.2 mm.

[0013] In one optional embodiment, the EPE film layer and the POE film layer are integrated and composited by splicing.

[0014] Secondly, this disclosure also provides a solar cell module, comprising: a photovoltaic glass layer, an upper encapsulant layer, a cell layer, a lower encapsulant layer, and a backsheet layer stacked sequentially from top to bottom; wherein the lower encapsulant layer is a composite encapsulant film as described above.

[0015] In one optional embodiment, the upper adhesive film layer is a transparent EPE adhesive film layer or a transparent EVA adhesive film layer.

[0016] In one optional embodiment, the thickness of the upper adhesive film layer ranges from 0.3 to 0.8 mm.

[0017] In one alternative embodiment, the cell layer comprises a gridless N-type TOPCon cell.

[0018] The beneficial effects of this utility model are that, based on the existing U-shaped composite encapsulation film, this composite structure encapsulation film addresses the characteristic that welding stress is more easily transmitted to the edge of the battery in gridless technology by changing the POE film layer at the edge to a pre-crosslinked POE with higher initial strength and modulus. This allows it to better support the battery and reduce microcracks during the welding process. At the same time, the thickened area at the edge can accurately compensate for the shrinkage difference of dissimilar materials during the lamination process, avoiding bow-shaped or wavy defects and ensuring the flatness of the module.

[0019] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and drawings.

[0020] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a composite encapsulation film provided in an embodiment of the present disclosure; Figure 2 This is a schematic diagram of the structure of a solar cell module provided in an embodiment of this disclosure.

[0023] In the picture: 1. Photovoltaic glass layer; 2. Upper encapsulant layer; 3. Cell layer; 4. Lower encapsulant layer; 5. Backsheet layer; 41. EPE film layer; 42. POE film layer. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0025] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0026] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0027] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0028] Regarding CN222374621U, the inventors further investigated and discovered the following defects: 1. Inability to effectively resist welding impact, with the risk of hidden cracks: The EVA and POE used in CN222374621U are conventional uncrosslinked or low-crosslinked films with low initial modulus. During the cell welding process before lamination, they cannot provide sufficient mechanical support for the edge area of ​​the cell, reducing the yield of the module.

[0029] 2. Homogeneous materials exhibit uniform interface shrinkage, failing to compensate for stress: The EVA and POE used in CN222374621U are both homogeneous films, typically employing the same thickness and a straight bonding interface. During the lamination heating process, the different coefficients of thermal expansion and shrinkage rates of the two materials lead to internal stress in the interface area. This stress cannot be effectively released or compensated, which is one of the important reasons for warping or wave-pattern defects after module lamination, affecting the flatness and appearance quality of the module.

[0030] 3. Simple structure and performance, not optimized for cutting-edge technologies: The core concept of CN222374621U only stays at the basic functional level of "edge anti-PID". Its simple "EVA+POE" material and structural design does not consider how to adapt to new types of batteries that are extremely sensitive to moisture (such as HJT). The thickness of its edge POE layer is the same as that of the center. Although the moisture barrier capability is improved, it is not maximized. For a component that pursues ultra-high reliability with a lifespan of more than 25 years, its edge protection is still insufficient.

[0031] The shortcomings of the above solutions are the result of the inventor's practical experience and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure below should be considered as the inventor's contribution to this disclosure.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] The following detailed description, with reference to the accompanying drawings, describes some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] Please see Figure 2 ,like Figure 2 As shown, this disclosure provides a composite structure encapsulation film, comprising: an EPE film layer located in the central region and a POE film layer surrounding the periphery, together forming a U-shaped planar structure; wherein, the EPE film layer is not pre-crosslinked or has a crosslinking degree <10%, and the pre-crosslinking degree of the POE film layer ranges from 10% to 40%; and the thickness of the POE film layer is 0.2 to 0.4 mm greater than the thickness of the EPE film layer.

[0035] Specifically, the central area, being larger, utilizes EPE film, which is less expensive than POE but has better water resistance than EVA, significantly reducing overall material costs while ensuring the main performance. The edge areas, being critical weak points, are reinforced with POE film, offering superior anti-PID performance, ensuring the highest component reliability. This structure achieves near-full POE encapsulation performance at minimal cost.

[0036] Specifically, POE material itself possesses extremely high volume resistivity and excellent hydrolysis resistance. Its precise application to the perimeter of solar cell arrays can effectively suppress the PID effect caused by moisture intrusion and ion migration at the edges, providing crucial protection for high-efficiency cells sensitive to PID.

[0037] In some embodiments, specifically, the width of the POE film layer is 50-70 mm to ensure an effective and economical protective band is formed at the edge of the cell array.

[0038] In some embodiments, specifically, the thickness of the EPE film layer ranges from 0.3 to 0.8 mm.

[0039] In some embodiments, the thickness of the POE film layer specifically ranges from 0.5 to 1.2 mm.

[0040] In some embodiments, the EPE film layer and the POE film layer are spliced ​​together to achieve an integrated composite, ensuring a seamless connection between the two layers and avoiding delamination or bubbles.

[0041] Please see Figure 1 ,like Figure 1 As shown in the embodiments of this disclosure, a solar cell module is also provided, comprising: a photovoltaic glass layer, an upper encapsulant layer, a cell layer, a lower encapsulant layer, and a backsheet layer stacked sequentially from top to bottom; wherein the lower encapsulant layer is a composite structure encapsulant film as described above.

[0042] In some embodiments, the upper adhesive film layer is specifically a transparent EPE adhesive film layer or a transparent EVA adhesive film layer.

[0043] In some embodiments, specifically, the thickness of the upper adhesive film layer ranges from 0.3 to 0.8 mm.

[0044] In some embodiments, specifically, the cell layer comprises a gridless N-type TOPCon cell.

[0045] Example 1: Reference Figure 1, the present utility model provides a solar cell module packaged based on an EPE-POE composite structure, whose layered structure comprises from top to bottom: a photovoltaic glass layer 1, an upper adhesive film layer 2, a cell sheet layer 3, a lower adhesive film layer 4 and a back sheet layer 5.

[0046] The lower adhesive film layer 4 is made of a rectangular un-precrosslinked EPE adhesive film layer (41) and a partially precrosslinked POE adhesive film layer (42) surrounding the EPE adhesive film layer by splicing, forming a "loop-shaped" structure.

[0047] The precrosslinking degree of the POE adhesive film layer (42) is controlled at 15%.

[0048] The POE adhesive film layer (42) has a thickness of 0.75mm and a width of 60mm.

[0049] The EPE adhesive film layer (41) has a thickness of 0.5mm.

[0050] The upper adhesive film layer 2 is a transparent EPE adhesive film layer with a thickness of 0.5mm.

[0051] The cell sheet layer 3 is an N-type TOPCon cell sheet adopting zero busbar (0BB) technology.

[0052] The preparation method of this embodiment: After preparing the lower adhesive film layer (4) by splicing according to the above parameters, lamination is performed according to the conventional stacking sequence (glass - upper adhesive film layer - cell sheet - lower adhesive film layer - back sheet). Then the module is placed into a laminator, laminated at 150°C for 15 minutes, and cooled to obtain the finished module.

[0053] Example 2: A solar cell module packaged based on an EPE-POE composite structure in this example all refers to Example 1, and the difference from Example 1 is: In this example, the precrosslinking degree of the POE layer (42) of the lower adhesive film layer is changed to 25%, the thickness is changed to 0.85mm, and the width is changed to 70mm. The subsequent preparation process all refers to Example 1.

[0054] Comparative Example 1: A solar cell module packaged based on an EPE-POE composite structure in this comparative example refers to Example 1, and the difference from Example 1 is: The entire lower adhesive film layer is EPE.

[0055] Comparative Example 2: A solar cell module packaged based on an EPE-POE composite structure in this comparative example refers to Example 1, and the difference from Example 1 is: The entire lower adhesive film layer is POE.

[0056] Comparative Example 3 This comparative example provides a solar cell module encapsulated based on an EPE-POE composite structure, which refers to Embodiment 1, and differs from Embodiment 1 in that: the lower adhesive film layer is in a "square ring" shape, with a central EVA layer and an edge POE layer, wherein the edge POE layer is non-pre-crosslinked and has the same thickness as the central EVA.

[0057] Specifically, the test results are shown in Table 1 below: Table 1

[0058] Wherein, the test method for PID attenuation rate in the edge region adopts the IEC 62804-1 standard, under conditions of 85°C, 85% RH, 96h; the water vapor transmission rate is measured by MOCON at 40°C and 90% RH; the warpage height after lamination is tested by a platform measurement method; the hidden crack rate after welding is tested by EL detection after 0BB process; the relative material cost index is calculated with full-layer EVA as 100.

[0059] Combined with the test data in Table 1, it can be concluded that: (1) A cost-effective breakthrough in PID resistance is achieved: the PID resistance of the embodiments of the present invention (-1.2% / -0.9%) far exceeds that of Comparative Example 1 (full-layer EPE, -6.5%) and Comparative Example 3 (structure in the prior art patent, -2.0%), and is infinitely close to the top performance level of Comparative Example 2 (full-layer POE, -0.8%). This shows that by accurately applying the expensive POE material to the most critical edge region, the present invention achieves almost the same highest reliability at a significantly lower cost than the full-POE solution (cost index 125 / 128 vs. 180).

[0060] (2) Excellent edge water-blocking and sealing advantages are established: the water vapor transmission rate of the embodiments of the present invention (2.0 / 1.8 g / m²·day) is the lowest among all comparison solutions, and is even better than that of the full-layer EPE solution (2.5). This proves that the combination of "EPE center (excellent water resistance) + POE edge (strong sealing performance)" produces a synergistic effect, constructs a double water-blocking barrier, and especially optimizes the path of water vapor intrusion at the edge of the module to the extreme, providing a solid foundation for long-term service life.

[0061] (3) The problem of lamination warping is fundamentally solved: The warping height of this utility model embodiment (1.5 / 1.3 mm) is much lower than that of Comparative Example 3 (existing patent structure, 4.2 mm), and even better than that of full-layer POE (1.8 mm). This directly confirms that the core innovation of this utility model - the structural design of "partially pre-crosslinked POE frame" and "center-edge thickness difference" - successfully compensates for the thermal shrinkage differences of different materials and solves the component flatness defects caused by internal stress that have long plagued the industry.

[0062] (4) Significantly improved yield of advanced manufacturing processes: For advanced technologies such as OBB, the microcrack rate of this embodiment (0.4% / 0.3%) is lower than that of all comparative examples, including full-layer POE (0.5%). This highlights the mechanical support provided by the partially pre-crosslinked POE frame in the welding process, effectively protecting the fragile battery cells and directly translating into higher production yield and better mechanical reliability.

[0063] (5) Optimal balance of comprehensive performance: In summary, this utility model does not simply trade off performance against cost, but achieves top-level reliability, excellent flatness, ultra-high production yield, and significant cost advantages through ingenious structural and material design. As shown in Table 1, it is superior to the closest prior art (Comparative Example 3) in all key indicators, and in comparison with the top-performance solution (Comparative Example 2), it achieves a huge cost advantage with a small performance difference, demonstrating outstanding comprehensive competitiveness.

[0064] In summary, this composite structure encapsulation film, based on the existing U-shaped composite encapsulation film, addresses the characteristic that welding stress is more easily transmitted to the edge of the battery in gridless technology by replacing the POE film layer at the edge with pre-crosslinked POE with higher initial strength and modulus. This allows it to better support the battery and reduce microcracks during the welding process. At the same time, the thickened area at the edge can accurately compensate for the shrinkage difference of dissimilar materials during the lamination process, avoiding bow-shaped or wavy defects and ensuring the flatness of the module.

[0065] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A composite structure encapsulating film, characterized in that, include: The EPE film layer (41) located in the central area and the POE film layer (42) surrounding the periphery together form a U-shaped planar structure; Wherein, the EPE film layer (41) is not pre-crosslinked or has a crosslinking degree of <10%, and the POE film layer (42) has a pre-crosslinking degree ranging from 10% to 40%; Furthermore, the thickness of the POE film layer (42) is 0.2 to 0.4 mm greater than the thickness of the EPE film layer (41).

2. The composite structure encapsulating film as described in claim 1, characterized in that, The width of the POE film layer (42) is 50-70 mm.

3. The composite structure encapsulating film as described in claim 1, characterized in that, The thickness of the EPE film layer (41) ranges from 0.3 to 0.8 mm.

4. The composite structure encapsulating film as described in claim 1, characterized in that, The thickness of the POE film layer (42) ranges from 0.5 to 1.2 mm.

5. The composite structure encapsulating film as described in claim 1, characterized in that, The EPE film layer (41) and POE film layer (42) are integrated and composited by splicing.

6. A solar cell module, characterized in that, include: The photovoltaic glass layer (1), upper encapsulant layer (2), cell layer (3), lower encapsulant layer (4) and backsheet layer (5) are stacked sequentially from top to bottom. Wherein, the lower adhesive film layer (4) is a composite structure encapsulation film as described in any one of claims 1-5.

7. The solar cell module as described in claim 6, characterized in that, The upper adhesive layer (2) is a transparent EPE adhesive layer or a transparent EVA adhesive layer.

8. The solar cell module as described in claim 6, characterized in that, The thickness of the upper adhesive film layer (2) ranges from 0.3 to 0.8 mm.

9. The solar cell module as described in claim 6, characterized in that, The cell layer (3) includes a gridless N-type TOPCon cell.

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