Flexible solar panel and preparation method thereof

Abstract

The invention provides a flexible solar panel. The flexible solar panel sequentially comprises a back plate, a first EVA adhesive film, first epoxy resin glass fiber cloth, a battery piece, second epoxy resin glass fiber cloth, a second EVA adhesive film and an ETFE thin film from top to bottom, the flexible solar panel further comprises a copper net which enables the battery pieces to be connected in series. The preparation raw materials of the first epoxy resin glass fiber cloth and the second epoxy resin glass fiber cloth respectively and independently comprise glass fiber cloth and impregnation liquid; the impregnation liquid comprises 40-60 parts by weight of silicon dioxide modified epoxy resin, 40-60 parts by weight of MDI modified epoxy resin, 8-12 parts by weight of a curing agent, 8-12 parts by weight of inorganic powder and 180-210 parts by weight of a first solvent. The flexible solar panel has good impact resistance, high and low temperature cycle resistance, bending resistance and photoelectric conversion rate. The invention also provides a preparation method of the flexible solar panel.

Description

Technical Field

[0001] This application relates to the technical field of photovoltaic products, and particularly to a flexible solar panel and a preparation method thereof. Background Art

[0002] Flexible solar panels are innovative products based on thin-film solar cell technology, featuring being thin, light, portable, and bendable. The application scenarios of flexible solar panels are very extensive, covering multiple fields such as automobiles and ships, distributed power generation, building integration, electronic product charging, and RVs. Due to the applications in multiple fields, the market share of flexible solar panels has shown a significant growth trend in recent years.

[0003] Flexible solar panels usually use light and flexible materials as the substrate. Although these materials have good flexibility and lightness, they are relatively weak in mechanical strength and impact resistance. Therefore, flexible solar panels are prone to cracking under external forces. Encapsulation materials are prone to aging, resulting in a decline in the protection performance of the encapsulation layer, thereby affecting the stability of the battery cells. In addition, flexible solar panels are usually installed on curved surfaces or parts that need to be frequently bent. Under long-term bending, vibration, and harsh environments such as wind, frost, rain, and snow, the battery cells are prone to hidden cracks due to mechanical stress. If flexible solar panels are subjected to external impacts during installation, transportation, or use, it is also easy to cause hidden cracks in the battery cells.

[0004] The existence of hidden cracks will prevent part of the current of the battery cell from being normally output, resulting in partial failure of the battery cell and a significant decrease in the output power of the module. The further expansion of the crack will accelerate the power attenuation of the battery cell and shorten the service life of the module.

[0005] Therefore, it is necessary to provide a flexible solar panel that has good protection for battery cells. Summary of the Invention

[0006] In view of the above problems, the present invention provides a flexible solar panel, which successively includes from top to bottom: a backsheet, a first EVA film, a first epoxy resin fiberglass cloth, battery cells, a second epoxy resin fiberglass cloth, a second EVA film, and an ETFE film; the flexible solar panel further includes a copper mesh for connecting the battery cells in series. The preparation raw materials of the first epoxy resin fiberglass cloth and the second epoxy resin fiberglass cloth independently include fiberglass cloth and an impregnating solution, and the impregnating solution includes: 40 - 60 parts by weight of silica-modified epoxy resin, 40 - 60 parts by weight of MDI-modified epoxy resin, 8 - 12 parts by weight of a curing agent, 8 - 12 parts by weight of inorganic powder, and 180 - 210 parts by weight of a first solvent.

[0007] Through the above technical solutions, silica-modified epoxy resin can significantly improve the mechanical properties, thermal stability and durability of epoxy resin. Nano-silica has special optical properties, which can reflect ultraviolet rays and absorb infrared rays, thereby reducing the degradation effect of ultraviolet rays on epoxy resin and increasing the anti-aging performance. MDI-modified epoxy resin has excellent heat resistance, mechanical properties and adhesion. By using silica-modified epoxy resin and MDI-modified epoxy resin in combination in the impregnating solution, on the one hand, the mechanical properties of the epoxy resin glass fiber cloth can be improved, and on the other hand, the affinity between the epoxy resin glass fiber cloth and the battery chip can be enhanced. Further, a good protective effect of the epoxy resin glass fiber cloth on the battery chip is achieved, making it have good impact resistance, high and low temperature cycle resistance, and bending resistance. Silica-modified epoxy resin and MDI-modified epoxy resin have a significant synergistic effect in improving the impact resistance, high and low temperature cycle resistance, and bending resistance of flexible solar panels.

[0008] Preferably, the preparation method of the first epoxy resin glass fiber cloth and the second epoxy resin glass fiber cloth includes: impregnating an alkali-free glass fiber cloth in the above impregnating solution, drying, and hot pressing to obtain an epoxy resin glass fiber cloth.

[0009] Preferably, the weight ratio of the alkali-free glass fiber cloth to the impregnating solution is 60:40.

[0010] Preferably, the copper mesh is screen-printed or laser-etched on the battery chip.

[0011] Preferably, the first solvent is acetone.

[0012] Preferably, the weight ratio of the silica-modified epoxy resin to the MDI-modified epoxy resin is 4-9:6.

[0013] Through the above technical solutions, by controlling the weight ratio of the silica-modified epoxy resin to the MDI-modified epoxy resin to 4-9:6, the epoxy resin glass fiber cloth has both good mechanical properties and affinity with the battery chip. When it is applied in a flexible solar panel, it can achieve a protective effect on the battery chip, making it impact-resistant, high and low temperature cycle-resistant, and bending-resistant, thereby increasing the service life.

[0014] Preferably, the preparation method of the silica-modified epoxy resin includes: adding epoxy resin to a second solvent, adding silica, stirring and reacting, and removing the second solvent to obtain a silica-modified epoxy resin, and the weight ratio of the silica to the epoxy resin is 4-8:65.

[0015] Preferably, the silica is replaced with an equal weight of modified silica, and the modified silica is silica modified with a silane coupling agent.

[0016] Through the above technical solution, nano-silica is prone to agglomeration. By modifying the surface of silica with siloxane, the modification of epoxy resin with silica becomes more uniform, which can further improve the performance of silica-modified epoxy resin. Moreover, the silica-modified epoxy resin obtained after modification can cooperate better with MDI-modified epoxy resin. When used together, it is more conducive to enhancing the protection effect on the battery chip, and further improving the impact resistance, high and low temperature cycle resistance, and bending resistance of the flexible solar panel.

[0017] Preferably, the second solvent is acetone.

[0018] Preferably, the preparation method of the MDI-modified epoxy resin includes: adding epoxy resin into a third solvent, adding a catalyst and MDI (diphenylmethane diisocyanate), and reacting to obtain the MDI-modified epoxy resin.

[0019] Preferably, the weight ratio of the MDI to the epoxy resin is 14-18:65.

[0020] Preferably, the MDI is composed of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate with a mass ratio of 9-25:15.

[0021] Through the above technical solution, the two isocyanate groups of 4,4'-MDI are located at the para positions of the benzene ring, having high reactivity and symmetry. This symmetry enables 4,4'-MDI to form a more regular network structure during the reaction, thereby improving the mechanical properties and thermal stability of the material. One isocyanate group of 2,4'-MDI is located at the para position of the benzene ring, and the other is located at the ortho position. This asymmetric structure results in relatively low reactivity, but can provide better flexibility. The cooperation of 4,4'-MDI and 2,4'-MDI to modify epoxy resin can enable the MDI-modified epoxy resin to cooperate better with the silica-modified epoxy resin. When used together, it is more conducive to enhancing the protection effect on the battery chip, and improving the impact resistance, high and low temperature cycle resistance, and bending resistance of the flexible solar panel.

[0022] Preferably, the second solvent is methyl ethyl ketone.

[0023] In the second aspect of the present invention, the present invention provides a preparation method of the above flexible solar panel, including the following steps: encapsulating a backboard, a first EVA film, a first epoxy resin fiberglass cloth, a battery chip, a second epoxy resin fiberglass cloth, a second EVA film, and an ETFE film in sequence, and laminating to obtain the flexible solar panel.

[0024] Preferably, the preparation method of the flexible solar panel includes the following steps: Encapsulate the backplane, the first EVA film, the first epoxy resin fiberglass cloth, and the battery cells in sequence, and laminate them to obtain the pre-pressed component; Encapsulate the pre-pressed component, the second epoxy resin fiberglass cloth, the second EVA film, and the ETFE film in sequence, and laminate them to obtain the flexible solar panel.

[0025] Through the above technical solution, by encapsulating the first EVA film, the first epoxy resin fiberglass cloth, and the battery cells in sequence, pre-pressing, and then encapsulating the pre-pressed component, the second epoxy resin fiberglass cloth, the second EVA film, and the ETFE film in sequence and laminating them for the second time, tight encapsulation of the battery can be achieved. In particular, it can make the copper wire and the battery achieve a tighter combination, thereby improving the photoelectric conversion rate, impact resistance, resistance to high and low temperature cycles, and bending resistance.

[0026] The back is a CPC backplane.

[0027] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The present application provides a flexible solar panel. The battery cells of the flexible solar panel are protected by epoxy resin fiberglass cloth. The impregnating solution for preparing the epoxy resin fiberglass cloth includes silica-modified epoxy resin and MDI-modified epoxy resin. The silica-modified epoxy resin and the MDI-modified epoxy resin are used in combination. On the one hand, it can improve the mechanical properties of the epoxy resin fiberglass cloth, and on the other hand, it can improve the affinity between the epoxy resin fiberglass cloth and the battery cells, further realizing the good protection effect of the epoxy resin fiberglass cloth on the battery cells, making it have good impact resistance, high and low temperature cycle resistance, and bending resistance.

[0028] 2. The present application provides a preparation method for the above flexible solar panel. Through a specific lamination process, tight encapsulation of the battery is achieved. In particular, it can make the copper wire and the battery achieve a tighter combination, thereby improving the photoelectric conversion rate, impact resistance, resistance to high and low temperature cycles, and bending resistance. Detailed implementation manners

[0029] The present invention will be further described below in conjunction with specific embodiments. However, the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those conditions not specified in the following embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. The methods used, unless otherwise specified, are all conventional methods well-known in the art. The consumables and reagents used, unless otherwise specified, are all commercially available. Unless otherwise stated, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied to the present invention. The CPC backplane, EVA film, and ETFE film are all commercially available conventional materials for solar panels.

[0030] Preparation Example 1 Preparation of silica-modified epoxy resin: Add 65 parts by weight of bisphenol A epoxy resin E51 to 600 parts by weight of acetone. While stirring, add 6 parts by weight of nano-silica and stir for 3 h. Carry out vacuum distillation on the mixed solution to remove acetone, and obtain silica-modified epoxy resin.

[0031] Preparation Example 2 The difference between Preparation Example 2 and Preparation Example 1 is only that nano-silica is replaced with modified silica in equal weight. The preparation method of modified silica includes: adding nano-silica to a 3 wt% silane coupling agent (KH550) diluted with N-methylpyrrolidone, reacting for 6 h under a nitrogen atmosphere, centrifuging, and separating to obtain modified silica. The mass ratio of nano-silica to the silane coupling agent dilution is 1:20.

[0032] Preparation Example 3 Preparation of MDI-modified epoxy resin: Mix 65 parts by weight of bisphenol A epoxy resin E51 with 20 parts by weight of methyl ethyl ketone and heat to 80 °C. Then add 0.3 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol, 0.1 part by weight of boric acid, 0.15 part by weight of citric acid, 8 parts by weight of 4,4'-diphenylmethane diisocyanate, and 8 parts by weight of 2,4'-diphenylmethane diisocyanate, stir evenly, heat to 120 °C, and obtain MDI-modified epoxy resin after reacting for 1 h.

[0033] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 3 is only that the weight parts of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate raw materials in the preparation raw materials of MDI-modified epoxy resin are different. In Preparation Example 4, 4,4'-diphenylmethane diisocyanate is 6 parts by weight and 2,4'-diphenylmethane diisocyanate is 10 parts by weight.

[0034] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 3 is only that the weight parts of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in the raw materials for preparing the MDI-modified epoxy resin are different. In Preparation Example 5, 4,4'-diphenylmethane diisocyanate is 10 parts by weight and 2,4'-diphenylmethane diisocyanate is 6 parts by weight.

[0035] Preparation Example 6 Preparation of silica and MDI co-modified epoxy resin: Mix 65 parts by weight of bisphenol A epoxy resin E51 with 20 parts by weight of methyl ethyl ketone and heat to 80°C. Then add 0.3 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol, 0.1 parts by weight of boric acid, 0.15 parts by weight of citric acid, 8 parts by weight of 4,4'-diphenylmethane diisocyanate, 8 parts by weight of 2,4'-diphenylmethane diisocyanate, and 6 parts by weight of nano-silica, stir evenly, heat to 120°C, and react for 1 h to obtain silica and MDI co-modified epoxy resin.

[0036] Example 1 Preparation method of solar cell panel, including: Step 1): Prepare the impregnating solution: Mix 50 parts by weight of silica-modified epoxy resin, 50 parts by weight of MDI-modified epoxy resin, 9 parts by weight of dicyandiamide, 10 parts by weight of talcum powder, and 190 parts by weight of acetone to obtain the impregnating solution, wherein the silica-modified epoxy resin is prepared from Preparation Example 1 and the MDI-modified epoxy resin is prepared from Preparation Example 3; Step 2): Immerse the alkali-free glass fiber cloth in the impregnating solution obtained in Step 1). The weight ratio of the alkali-free glass fiber cloth to the impregnating solution is 60:40. Immerse for 6 h, dry, and hot press to obtain an epoxy resin glass fiber cloth (thickness 0.2 mm); Step 3): After texturing the surface of the battery chip, use screen printing or laser etching technology to inlay the electronic copper mesh on the surface of the battery chip, and use high-temperature curing technology to tightly bond the electronic copper mesh (thickness about 10 - 20 μm) with the battery chip. The copper mesh is designed in a grid layout to reduce resistance loss and improve current transmission efficiency.

[0037] Step 4): The solar cell panel from top to bottom is a CPC backplane, an EVA film (thickness 0.3 mm), the epoxy resin glass fiber cloth obtained in Step 2) (thickness 0.2 mm), the battery chip, the epoxy resin glass fiber cloth obtained in Step 2) (thickness 0.2 mm), an EVA film (thickness 0.3 mm), and an ETFE film (thickness 0.1 mm), First, encapsulate the CPC backplane, EVA film (thickness 0.3 mm), the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), and the solar cells in sequence, put them into a laminator, evacuate the air, with a lamination temperature of 135 °C, apply a pressure of 0.5 - 1 MPa, and keep it for 15 min to obtain a pre-pressed component; Then, encapsulate the pre-pressed component, the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), EVA film (thickness 0.3 mm), and ETFE film (thickness 0.1 mm) in sequence, put them into a laminator, evacuate the air, with a lamination temperature of 145 °C, apply a pressure of 1.5 - 2 MPa, keep it for 20 min, and then cool to obtain a solar cell panel.

[0038] Example 2 The difference between Example 2 and Example 1 is only that the weight parts of the silica-modified epoxy resin and the MDI-modified epoxy resin in the impregnating solution in step 1) are different. In Example 2, the silica-modified epoxy resin in the impregnating solution is 40 weight parts and the MDI-modified epoxy resin is 60 weight parts.

[0039] Example 3 The difference between Example 3 and Example 1 is only that the weight parts of the silica-modified epoxy resin and the MDI-modified epoxy resin in the impregnating solution in step 1) are different. In Example 3, the silica-modified epoxy resin in the impregnating solution is 60 weight parts and the MDI-modified epoxy resin is 40 weight parts.

[0040] Example 4 The difference between Example 4 and Example 1 is only that the silica-modified epoxy resin in the impregnating solution in step 1) is the silica-modified epoxy resin prepared in Preparation Example 2.

[0041] Example 5 The difference between Example 5 and Example 1 is only that the MDI-modified epoxy resin in the impregnating solution in step 1) is the MDI-modified epoxy resin prepared in Preparation Example 4.

[0042] Example 6 The difference between Example 6 and Example 1 is only that the MDI-modified epoxy resin in the impregnating solution in step 1) is the MDI-modified epoxy resin prepared in Preparation Example 5.

[0043] Example 7 Example 7 is different from Example 1 only in that the lamination process in step 4) is different. In Example 7, step 4) is as follows: Step 4): The solar panel, from top to bottom, is a CPC backsheet, an EVA film (thickness 0.3 mm), the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), solar cells, the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), an EVA film (thickness 0.3 mm), and an ETFE film (thickness 0.1 mm). First, encapsulate the solar cells, the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), an EVA film (thickness 0.3 mm), and an ETFE film (thickness 0.1 mm) in sequence, place them in a laminator, evacuate the air, the lamination temperature is 135 °C, apply a pressure of 0.5 - 1 MPa, and keep it for 15 min to obtain a pre-pressed component. Then, encapsulate the CPC backsheet, an EVA film (thickness 0.3 mm), the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), and the pre-pressed component in sequence, place them in a laminator, evacuate the air, the lamination temperature is 145 °C, apply a pressure of 1.5 - 2 MPa, keep it for 20 min, and then cool to obtain a solar panel.

[0044] Example 8 Example 8 is different from Example 1 only in that the lamination process in step 4) is different. In Example 8, step 4) is as follows: Step 4): The solar panel, from top to bottom, is a CPC backsheet, an EVA film (thickness 0.3 mm), the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), solar cells, the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), an EVA film (thickness 0.3 mm), and an ETFE film (thickness 0.1 mm). First, encapsulate the CPC backsheet, an EVA film (thickness 0.3 mm), the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), solar cells, the epoxy resin fiberglass cloth obtained in step 2) (thickness 0.2 mm), an EVA film (thickness 0.3 mm), and an ETFE film (thickness 0.1 mm) in sequence, place them in a laminator, evacuate the air, the lamination temperature is 135 °C, apply a pressure of 0.5 - 1 MPa, and keep it for 15 min to obtain a pre-pressed component; Then, place the pre-pressed component in a laminator, evacuate the air, the lamination temperature is 145 °C, apply a pressure of 1.5 - 2 MPa, keep it for 20 min, and then cool to obtain a solar panel.

[0045] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is only that in the impregnating solution of step 1), the silica-modified epoxy resin prepared in Preparation Example 1 is replaced with the MDI-modified epoxy resin prepared in Preparation Example 3 in equal weight.

[0046] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is only that in the impregnating solution of step 1), the MDI-modified epoxy resin prepared in Preparation Example 3 is replaced with the silica-modified epoxy resin prepared in Preparation Example 1 in equal weight.

[0047] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is only that the silica-modified epoxy resin prepared in Preparation Example 1 and the MDI-modified epoxy resin prepared in Preparation Example 3 are both replaced with the silica- and MDI-copolymer modified epoxy resin prepared in Preparation Example 6 in equal weight.

[0048] Detection: Using the equipment with the model XJCM-9A+ produced by Shaanxi Zhongshen Electric Energy Technology Co., Ltd., under standard test conditions (STC), the photoelectric conversion efficiency of the solar panels prepared in the examples and comparative examples was tested. The results are shown in Table 1.

[0049] The cell wafers of the examples and comparative examples are all 10 N-type TOPCon silicon wafers. 1. Through the double 85 high and low temperature cycle for 72 h (high temperature and high humidity 85 °C, humidity 85%; low temperature -20 °C, each temperature is maintained for 1 h), EL (electroluminescence) is used to detect whether there are hidden cracks. 2. The solar panels of the examples and comparative examples are laid flat on the ground, and a 500 g iron ball is lifted 50 cm each time and freely falls on the same position of the solar panel, and then EL (electroluminescence) is used to detect the number of free falls when hidden cracks first appear. 3. Bend the solar panel 90° longitudinally along the cell wafer 20 times, and use EL (electroluminescence) to detect whether there are hidden cracks. The results are shown in Table 1.

[0050] Table 1 Combined with Table 1, by comparing Comparative Examples 1 and 2 with Example 1, it can be seen that when the impregnating solution contains only silica-modified epoxy resin or only MDI-modified epoxy resin, the photoelectric conversion rate decreases, and the impact resistance, high and low temperature cycle resistance, and bending resistance of the flexible solar panel are significantly reduced.

[0051] Combined with Table 1, by comparing Comparative Example 3 with Example 1, it can be seen that when the silica- and MDI-copolymer modified epoxy resin is used in the impregnating solution, the impact resistance, high and low temperature cycle resistance, and bending resistance of the flexible solar panel are significantly reduced.

[0052] Comparing Examples 2 and 3 with Example 1 and combining with Table 1, it can be seen that when the weight ratio of silica-modified epoxy resin to MDI-modified epoxy resin in the impregnating solution changes, the photoelectric conversion rate of the flexible solar panel changes, and the impact resistance of the flexible solar panel changes significantly.

[0053] Comparing Example 4 with Example 1 and combining with Table 1, it can be seen that when the raw material of silica-modified epoxy resin in the impregnating solution changes from silica to silica modified by silane coupling agent, the photoelectric conversion rate of the flexible solar panel changes, and the impact resistance of the flexible solar panel becomes significantly better.

[0054] Comparing Examples 5 and 6 with Example 1 and combining with Table 1, it can be seen that when the weight ratio of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in the raw materials of MDI-modified epoxy resin in the impregnating solution changes, the photoelectric conversion rate of the flexible solar panel changes, and the impact resistance of the flexible solar panel changes significantly.

[0055] Comparing Examples 7 and 8 with Example 1 and combining with Table 1, it can be seen that when the lamination process of the flexible solar panel changes, the photoelectric conversion rate of the flexible solar panel changes significantly, and the impact resistance of the flexible solar panel changes significantly.

[0056] The above are all preferred embodiments of this application. The protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A flexible solar panel, characterized in that, From top to bottom, it successively includes: a back plate, a first EVA film, a first epoxy resin fiberglass cloth, solar cells, a second epoxy resin fiberglass cloth, a second EVA film, and an ETFE film; the flexible solar panel further includes a copper mesh for connecting the solar cells in series. The preparation raw materials of the first epoxy resin fiberglass cloth and the second epoxy resin fiberglass cloth independently include fiberglass cloth and an impregnating solution respectively. The impregnating solution includes: 40-60 parts by weight of silica-modified epoxy resin, 40-60 parts by weight of MDI-modified epoxy resin, 8-12 parts by weight of a curing agent, 8-12 parts by weight of an inorganic powder, and 180-210 parts by weight of a first solvent.

2. The flexible solar panel according to claim 1, characterized in that The copper mesh is etched in the solar cells.

3. The flexible solar panel according to claim 1, wherein The weight ratio of the silica-modified epoxy resin to the MDI-modified epoxy resin is 4-9:

6.

4. The flexible solar panel according to claim 1, wherein The preparation method of the silica-modified epoxy resin includes: adding epoxy resin into a second solvent, adding silica, stirring and reacting, and removing the second solvent to obtain the silica-modified epoxy resin. The weight ratio of the silica to the epoxy resin is 4-8:

65.

5. The flexible solar panel according to claim 4, wherein, The silica is replaced with an equal weight of modified silica, and the modified silica is silica modified with a silane coupling agent.

6. The flexible solar panel according to claim 1, wherein The preparation method of the MDI-modified epoxy resin includes: adding epoxy resin into a third solvent, adding a catalyst and MDI, and reacting to obtain the MDI-modified epoxy resin.

7. The flexible solar panel according to claim 6, wherein, The weight ratio of the MDI to the epoxy resin is 14-18:

65.

8. The flexible solar panel according to claim 6, wherein The MDI is composed of 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate with a mass ratio of 9-25:

15.

9. A method for preparing a flexible solar panel according to any one of claims 1-8, characterized in that, It includes the following steps: encapsulating the back plate, the first EVA film, the first epoxy resin fiberglass cloth, the solar cells, the second epoxy resin fiberglass cloth, the second EVA film, and the ETFE film in sequence and laminating to obtain the flexible solar panel.

10. The preparation method of the flexible solar panel according to claim 9, wherein, It includes the following steps: Encapsulating the back plate, the first EVA film, the first epoxy resin fiberglass cloth, and the solar cells in sequence and laminating to obtain a pre-pressed component; Encapsulating the pre-pressed component, the second epoxy resin fiberglass cloth, the second EVA film, and the ETFE film in sequence and laminating to obtain the flexible solar panel.

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