Preparation and application of highly absorbent hydrogel for heat dissipation of solar cell backplane

Abstract

The present invention relates to the preparation and application of a highly water-absorbent hydrogel for heat dissipation of a solar cell back panel. A monomer solution is first prepared, and then an initiator solution is prepared. The monomer solution and the initiator solution are then mixed to obtain a hydrogel prepolymer solution. The hydrogel prepolymer solution is used to cast and gel the solar cell back panel, and finally a highly water-absorbent hydrogel coating is prepared on the solar cell back panel. The water content in the hydrogel coating can be as high as 90% or more. Since water has the highest latent heat (~40 kJ mol ‑1 ), water evaporation can take away a lot of heat, thereby achieving the purpose of heat dissipation. Therefore, the present invention can effectively improve the heat dissipation performance of the solar cell back panel by adding a highly water-absorbent hydrogel coating to the solar cell back panel, and can achieve continuous heat dissipation for a long time.

Description

Technical Field

[0001] The invention belongs to the technical field of heat dissipation materials, and in particular relates to a preparation method and application of a highly water-absorbent hydrogel coating used for heat dissipation of a solar cell back panel. Background Art

[0002] Solar cells (Solar panels) are devices that absorb sunlight and convert solar radiation energy directly or indirectly into electrical energy through photoelectric effect or photochemical effect. The main material of most solar cells is silicon, but the high production cost limits their large-scale use. Compared with ordinary batteries and rechargeable batteries, solar cells are more energy-saving and environmentally friendly green products. Solar cells are mainly composed of tempered glass, EVA, battery cells, back panels, aluminum alloy protective laminates, junction boxes, and silica gel.

[0003] With the development of society, people's awareness of sustainable development has gradually increased, and the demand for the development and utilization of clean and renewable energy such as solar energy is growing. However, the temperature rise caused by solar radiation during the use of solar cells will cause the power generation efficiency of solar cell modules to be significantly reduced.

[0004] At present, the main methods to solve the heat dissipation of solar panels include: 1) solar cell backplane structural design such as heat dissipation fins, pipes, etc. to enhance heat conduction and heat dissipation; 2) preparation of radiation heat dissipation coating to shield incident sunlight outside the effective wavelength. However, the above methods are often complex in structure and have little heat dissipation effect. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a preparation method and application of a highly absorbent hydrogel coating for heat dissipation of a solar cell back panel. The highly absorbent hydrogel described in the present invention is a material with a very high water content. By adding the highly absorbent hydrogel coating to the solar cell back panel, the heat dissipation performance of the solar cell back panel can be effectively improved, and continuous heat dissipation can be achieved for a long time.

[0006] The technical solution adopted by the present invention is:

[0007] A method for preparing a highly water-absorbent hydrogel coating for heat dissipation of a solar cell back panel comprises the following steps:

[0008] (1) Preparation of monomer solution: preparing a water-soluble olefin monomer solution, and adding a water-soluble olefin monomer cross-linking agent to the water-soluble olefin monomer solution;

[0009] (2) Preparation of initiator solution: preparing an initiator solution;

[0010] (3) Preparation of hydrogel prepolymer solution: The monomer solution of step (1) and the initiator solution of step (2) are fully mixed at a volume ratio of 100:1 to obtain a hydrogel prepolymer solution;

[0011] (4) The hydrogel prepolymer solution of step (3) is cast and gelled on the back panel of a solar cell module to obtain the highly absorbent hydrogel coating.

[0012] In step (1), the water-soluble olefin monomer solution is a water-soluble olefin monomer solution with a mass fraction of 3-30%.

[0013] In step (1), the water-soluble olefin monomer is an acrylamide monomer.

[0014] The acrylamide monomer is one or a mixture of acrylamide, methacrylamide, diacetone acrylamide and N-isopropyl acrylamide.

[0015] The water-soluble olefin monomer cross-linking agent is a water-soluble olefin monomer cross-linking agent with a functionality of ≥2, and the mass ratio of the water-soluble olefin monomer cross-linking agent to the water-soluble olefin monomer is 0.1-5%.

[0016] The water-soluble olefin monomer cross-linking agent is N,N'-methylenebisacrylamide.

[0017] In step (2), the initiator is a water-soluble thermal initiator or a water-soluble photoinitiator.

[0018] The mass volume concentration of the water-soluble thermal initiator is 5-20%; preferably, the water-soluble thermal initiator is ammonium persulfate;

[0019] The mass volume concentration of the water-soluble photoinitiator is 3-15%; preferably, the water-soluble photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone.

[0020] In step (3), for a thermal initiation system, a catalyst may be added.

[0021] In step (4), the thickness of the hydrogel coating is controlled by controlling the volume of the hydrogel prepolymer solution.

[0022] The highly water-absorbent hydrogel coating prepared by the method is used in heat dissipation of a solar cell back panel.

[0023] The beneficial effects of the present invention are:

[0024] The highly absorbent hydrogel coating used for heat dissipation of the solar cell back panel of the present invention is prepared by first preparing a monomer solution, then preparing an initiator solution, and then mixing the monomer solution and the initiator solution to obtain a hydrogel prepolymer solution. The hydrogel prepolymer solution is used to cast and gel on the solar cell back panel, and finally a highly absorbent hydrogel coating is prepared on the solar cell back panel. The water content in the hydrogel coating can be as high as 90% or more. Since water has the highest latent heat (~40kJ mol -1 ), water evaporation can take away a lot of heat, thereby achieving the purpose of heat dissipation. Therefore, the present invention can effectively improve the heat dissipation performance of the solar cell back panel by adding a highly absorbent hydrogel coating to the solar cell back panel, and can achieve continuous heat dissipation for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a schematic diagram of the structure of a solar cell module with a highly water-absorbent hydrogel coating as described in Example 1.

[0027] In the figure, 1-solar cell module, 11-solar cell module frame, 2-highly absorbent hydrogel coating. DETAILED DESCRIPTION

[0028] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0029] The solar cell modules in the following embodiments and experimental examples are described by taking a monocrystalline silicon photovoltaic solar cell module as an example.

[0030] Example 1

[0031] This embodiment provides a solar cell module heat dissipation system based on a highly water-absorbent hydrogel coating, the structure of which is as follows: Figure 1As shown, it includes a solar cell assembly 1 and a highly absorbent hydrogel coating 2. The size of the solar cell assembly 1 is 30 cm×30 cm. The highly absorbent hydrogel coating 2 is located in a frame 11 on the back of the solar cell assembly 1 and is in direct contact with the back plate of the solar cell assembly 1.

[0032] The method for preparing the highly water-absorbent hydrogel coating on the surface of the solar cell back sheet comprises the following steps:

[0033] (1) Preparation of monomer solution: using water as solvent, preparing a two-component monomer solution of acrylamide and N-isopropylacrylamide with a total mass fraction of 20%, wherein the mass ratio of acrylamide to N-isopropylacrylamide is 4:1, and adding a monomer crosslinking agent N,N′-methylenebisacrylamide with a functionality of ≥2 to the two-component monomer solution; the mass ratio of the monomer crosslinking agent to the monomer is 0.5%;

[0034] (2) Preparation of water-soluble thermal initiator solution: using water as solvent, prepare a thermal initiator ammonium persulfate solution with a mass volume concentration of 10%;

[0035] (3) Preparation of hydrogel prepolymer solution: Under ice bath conditions, the monomer solution of step (1) and the initiator solution of step (2) were fully mixed at a volume ratio of 100:1, and a catalyst of tetramethylethylenediamine was added at an amount of 0.5 μL / mL to obtain a hydrogel prepolymer solution;

[0036] (4) 180 mL of the hydrogel prepolymer solution of step (3) was cast on the surface of the solar cell back panel and allowed to stand at room temperature for 3 h until gelation occurred, thereby finally obtaining a highly absorbent hydrogel coating with a thickness of 2 mm on the surface of the solar cell back panel.

[0037] Example 2

[0038] The only difference between this embodiment and embodiment 1 is that the casting volume of the hydrogel prepolymer solution is 270 mL, and the thickness of the prepared highly absorbent hydrogel coating is 3 mm.

[0039] Example 3

[0040] The difference between this embodiment and embodiment 1 is that the highly absorbent hydrogel coating and the preparation method are different. The preparation method of the highly absorbent hydrogel coating in this embodiment comprises the following steps:

[0041] (1) Preparation of monomer solution: using water as solvent, preparing a 30% by mass diacetone acrylamide monomer solution, adding a monomer crosslinking agent N,N′-methylenebisacrylamide having a functionality of ≥2 to the diacetone acrylamide monomer solution; the mass ratio of the monomer crosslinking agent to the diacetone acrylamide is 1%;

[0042] (2) Preparation of water-soluble thermal initiator solution: using water as solvent, prepare a thermal initiator ammonium persulfate solution with a mass volume concentration of 20%;

[0043] (3) Preparation of hydrogel prepolymer solution: Under ice bath conditions, the monomer solution of step (1) and the initiator solution of step (2) were fully mixed at a volume ratio of 100:1, and a catalyst tetramethylethylenediamine was added at an amount of 2 μL / mL to obtain a hydrogel prepolymer solution;

[0044] (4) 180 mL of the hydrogel prepolymer solution in step (3) was cast on the surface of the solar cell back panel and allowed to stand at room temperature for 4 h until gelation, and finally a film with a thickness of 1.50 mm was prepared on the surface of the solar cell back panel. 2 mm highly absorbent hydrogel coating.

[0045] Example 4

[0046] The difference between this embodiment and embodiment 1 is that the highly absorbent hydrogel coating and the preparation method are different. The preparation method of the highly absorbent hydrogel coating in this embodiment comprises the following steps:

[0047] (1) Preparation of monomer solution: using water as solvent, preparing a 20% by mass acrylamide monomer solution, adding a monomer crosslinking agent N,N′-methylenebisacrylamide having a functionality of ≥2 to the acrylamide monomer solution; the mass ratio of the monomer crosslinking agent to acrylamide is 0.5%;

[0048] (2) Preparation of water-soluble photoinitiator solution: using water as solvent, prepare 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone with a mass volume concentration of 3%;

[0049] (3) Preparation of hydrogel prepolymer solution: The monomer solution of step (1) and the initiator solution of step (2) are fully mixed at a volume ratio of 100:1 to obtain a hydrogel prepolymer solution;

[0050] (4) 360 mL of the hydrogel prepolymer solution of step (3) was cast on the surface of the solar cell back panel, and irradiated under 365 nm ultraviolet light for 5 min to form a gel, and finally a highly absorbent hydrogel coating with a thickness of 4 mm was prepared on the surface of the solar cell back panel.

[0051] Example 5

[0052] The difference between this embodiment and embodiment 1 is that the highly absorbent hydrogel coating and the preparation method are different. The preparation method of the highly absorbent hydrogel coating in this embodiment comprises the following steps:

[0053] (1) Preparation of monomer solution: using water as solvent, preparing a 20% by mass acrylamide monomer solution, adding a monomer crosslinking agent N,N′-methylenebisacrylamide having a functionality of ≥2 to the acrylamide monomer solution; the mass ratio of the monomer crosslinking agent to acrylamide is 0.5%;

[0054] (2) Preparation of water-soluble photoinitiator solution: using water as solvent, prepare 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone with a mass volume concentration of 15%;

[0055] (3) Preparation of hydrogel prepolymer solution: The monomer solution of step (1) and the initiator solution of step (2) are fully mixed at a volume ratio of 100:1 to obtain a hydrogel prepolymer solution;

[0056] (4) 450 mL of the hydrogel prepolymer solution of step (3) was cast on the surface of the solar cell back panel, and irradiated under 365 nm ultraviolet light for 10 min until gelation, thereby finally obtaining a highly absorbent hydrogel coating with a thickness of 5 mm on the surface of the solar cell back panel.

[0057] Experimental Example 1

[0058] The solar cell back sheet with hydrogel coating prepared in Example 1 was placed in an outdoor sunlight environment, and a solar cell back sheet without hydrogel coating was used as a comparative example. The atmospheric temperature, atmospheric humidity, light intensity, and average temperature of the solar cell panel assembly at the measurement time point were recorded every hour. The experimental data were analyzed to evaluate the heat dissipation effect of the hydrogel coating.

[0059] The results are shown in Table 1.

[0060] Table 1

[0061]

[0062]

[0063] It can be seen from Table 1 that under the same outdoor sunlight environment, the solar cell back panel coated with the super absorbent hydrogel coating of the present invention can effectively improve the heat dissipation of the solar cell back panel, compared with the solar cell back panel not coated with the super absorbent hydrogel coating, and significantly reduce the average temperature of the solar cell module.

[0064] Experimental Example 2

[0065] The solar cell back sheet with hydrogel coating prepared in Example 2 was placed in an outdoor sunlight environment, and a solar cell back sheet without hydrogel coating was used as a comparative example, and parameters such as atmospheric temperature, atmospheric humidity, light intensity, and average temperature of solar cell panel components at the measurement time point were recorded every hour. The experimental data were analyzed to evaluate the heat dissipation effect of the hydrogel coating.

[0066] The results are shown in Table 2.

[0067] Table 2

[0068]

[0069]

[0070] It can be seen from Table 2 that under the same outdoor sunlight environment, the solar cell back panel coated with the super absorbent hydrogel coating of the present invention can effectively improve the heat dissipation of the solar cell back panel, compared with the solar cell back panel not coated with the super absorbent hydrogel coating, and significantly reduce the average temperature of the solar cell module.

[0071] As an optional embodiment, the arrangement of the highly absorbent hydrogel coating on the solar cell back panel can be prepared by directly casting a prepolymer solution to prepare the coating, or by combining or compounding a prepolymer solution with other materials such as porous materials, particles, etc. and then casting the coating.

[0072] As an optional implementation, when the highly absorbent hydrogel is combined or compounded with other materials, the other materials can be pre-fixed on the back of the solar cell module using an adhesive, or the hydrogel prepolymer solution can be blended or compounded with other materials and then cast into a gel to prepare a coating.

[0073] As an optional embodiment, the functions of the material combined or compounded with the hydrogel prepolymer solution include hydrogel fixation, reinforcement, and radiation cooling enhancement.

[0074] As an optional implementation, a water replenishment device may be provided on the outside of the highly absorbent hydrogel coating, including but not limited to intermittent spraying, water reabsorption in a high humidity environment, etc. The water replenishment device may also be used for daily cleaning of the solar panel surface.

[0075] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a highly water-absorbent hydrogel coating for heat dissipation of a solar cell back panel, characterized in that: The following steps are involved: (1) Preparation of monomer solution: preparing a water-soluble olefin monomer solution, and adding a water-soluble olefin monomer cross-linking agent to the water-soluble olefin monomer solution; The water-soluble olefin monomer is an acrylamide monomer, and the acrylamide monomer is one or a mixture of acrylamide, methacrylamide, diacetone acrylamide, and N-isopropyl acrylamide; The water-soluble olefin monomer solution is a water-soluble olefin monomer solution with a mass fraction of 3-30%; The water-soluble olefin monomer cross-linking agent is a water-soluble olefin monomer cross-linking agent with a functionality of ≥2, and the mass ratio of the water-soluble olefin monomer cross-linking agent to the water-soluble olefin monomer is 0.1-5%; (2) Preparation of initiator solution: prepare the initiator solution; The initiator is a water-soluble thermal initiator or a water-soluble photoinitiator; the mass volume concentration of the water-soluble thermal initiator is 5-20%; the water-soluble thermal initiator is ammonium persulfate; The mass volume concentration of the water-soluble photoinitiator is 3-15%; the water-soluble photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone; (3) Preparation of hydrogel prepolymer solution: the monomer solution of step (1) and the initiator solution of step (2) are fully mixed at a volume ratio of 100:1 to obtain a hydrogel prepolymer solution; For the thermal initiation system, a catalyst is also added, and the catalyst is tetramethylethylenediamine; (4) The hydrogel prepolymer solution of step (3) is cast and gelled on the back panel of a solar cell module to obtain the highly absorbent hydrogel coating.

2. The method for preparing a highly water-absorbent hydrogel coating for heat dissipation of a solar cell back panel according to claim 1, characterized in that: The water-soluble olefin monomer cross-linking agent is N,N'-methylenebisacrylamide.

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