Light conversion agent, packaging adhesive film and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic materials, in particular to a light conversion agent, a packaging adhesive film and a photovoltaic module. The preparation method of the light conversion agent comprises the following steps: heating and dissolving compound powder as shown in a formula I in a first solvent, cooling and crystallizing, and collecting a solid; the first solvent is prepared from at least one of ethyl acetate, N-methyl-2-pyrrolidone and acetone. The fluorescence quantum efficiency of the light conversion agent provided by the invention at room temperature can reach up to 97.12%, and compared with the existing light conversion agent, the light conversion agent provided by the invention has the advantages of high fluorescence quantum efficiency, good ultraviolet resistance and the like. According to the photovoltaic module prepared by adopting the packaging adhesive film disclosed by the invention, the power of the module can be remarkably improved, and the power attenuation of the module after ultraviolet radiation can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic materials, and in particular to a photoconversion agent, a packaging adhesive film and a photovoltaic module. Background Art

[0002] Heterojunction cells have the advantages of simple structure, low process temperature, good passivation effect, high open circuit voltage, good temperature characteristics, and double-sided power generation. They are one of the main directions of high conversion efficiency solar cells. However, there are some defects and potential defects inside the amorphous silicon layer of heterojunction cells, which will cause the cell efficiency to decay. At present, in order to address the ultraviolet attenuation of heterojunction cells, improvements are being made on the one hand from the design of the cell passivation layer structure, and on the other hand from the packaging material.

[0003] The existing method of improving packaging materials is to shield ultraviolet rays and use UV cut-off films to protect heterojunction cells. However, while this method protects the cells, it also shields ultraviolet rays that may have a gain effect on power generation, resulting in a loss of component power.

[0004] Light transfer film is obtained by adding wavelength conversion material, i.e. light conversion agent, to high-transmittance film. Light conversion agent absorbs ultraviolet light and converts it into usable blue light, which can protect the cell from being damaged by ultraviolet light while utilizing the energy of ultraviolet light for efficiency enhancement. Therefore, light transfer film has the performance of UV cut-off film and has a power output that is no less than that of high-transmittance film.

[0005] Existing photoconversion agents mainly include organic fluorescent pigments, rare earth organic complexes, rare earth inorganic compounds, CdSe quantum dots or perovskite quantum dots, etc. The fluorescence quantum efficiency of the photoconversion agent is very important, and currently, silane coupling agents or silicon dioxide are mainly used to modify the photoconversion agent to improve the fluorescence quantum efficiency, etc., but these modification methods have limitations.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] One object of the present invention is to provide a photoconversion agent, which fundamentally improves the fluorescence quantum efficiency of the photoconversion agent itself and has excellent ultraviolet resistance. When used, there is no need to further modify the photoconversion agent.

[0008] Another object of the present invention is to provide a packaging film, comprising the above-mentioned photoconversion agent.

[0009] Another object of the present invention is to provide a photovoltaic module, comprising the above-mentioned packaging film.

[0010] In order to achieve the above-mentioned object of the present invention, the present invention provides a photoconversion agent having a structure as shown in Formula I:

[0011]

[0012] The preparation method of the photoconversion agent comprises the following steps:

[0013] Dissolving the powder of the compound represented by formula I in a first solvent by heating, cooling and crystallizing, and collecting the solid;

[0014] The first solvent includes at least one of ethyl acetate, N-methyl-2-pyrrolidone and acetone.

[0015] In a specific embodiment of the present invention, after the heating and dissolving, the method further comprises: adding a second solvent for heat preservation treatment; the second solvent comprises at least one of water and acetonitrile.

[0016] In a specific embodiment of the present invention, the ratio of the first solvent to the powder is (10-100) mL: 1 g.

[0017] In a specific embodiment of the present invention, the volume ratio of the first solvent to the second solvent is 1:(1-10).

[0018] In a specific embodiment of the present invention, the temperature during the heating and dissolving is 55 to 85°C.

[0019] In a specific embodiment of the present invention, during the heat preservation treatment, the temperature is 55 to 85° C. and the time is 3 to 5 hours.

[0020] In a specific embodiment of the present invention, the temperature reduction crystallization includes: cooling to -15 to 15°C.

[0021] Another aspect of the present invention provides a packaging adhesive film, comprising a film body and any one of the above-mentioned photoconversion agents dispersed in the film body.

[0022] In a specific embodiment of the present invention, in the packaging film, the content of the light conversion agent is 0.01% to 0.55%.

[0023] Another aspect of the present invention provides a photovoltaic module, comprising any one of the above-mentioned packaging films.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The photoconversion agent provided by the present invention has a fluorescence quantum efficiency of up to 97.12% at room temperature, which has the advantages of high fluorescence quantum efficiency and good UV resistance compared with existing photoconversion agents;

[0026] (2) The photoconversion agent of the present invention does not require modification and can be directly used in the packaging film, which reduces the process and ensures the photoconversion effect; the photovoltaic module prepared using the packaging film of the present invention can significantly increase the module power and reduce the power attenuation of the module after ultraviolet irradiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 An X-ray powder diffraction (XPRD) pattern of the compound powder represented by formula I provided by the present invention;

[0029] Figure 2 The X-ray powder diffraction (XPRD) pattern of the photoconversion agent provided in Example 1 of the present invention;

[0030] Figure 3 This is an X-ray powder diffraction (XPRD) pattern of the photoconversion agent provided in Example 2 of the present invention;

[0031] Figure 4 This is an X-ray powder diffraction (XPRD) pattern of the photoconversion agent provided in Example 3 of the present invention;

[0032] Figure 5 This is the X-ray powder diffraction (XPRD) pattern of the photoconversion agent provided in Example 4 of the present invention. DETAILED DESCRIPTION

[0033] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0034] Existing photoconversion agents mainly include organic fluorescent pigments, rare earth organic complexes, rare earth inorganic compounds, CdSe quantum dots or perovskite quantum dots, etc. On the one hand, the fluorescence quantum efficiency of current photoconversion agents is limited; on the other hand, the UV resistance of some photoconversion agents is slightly poor, and they need to be compounded for use. The compounding process is cumbersome, resulting in an increase in the process steps, which limits their application in the photovoltaic field. Based on this, the present invention provides a photoconversion agent with both high fluorescence quantum efficiency and UV resistance.

[0035] In one aspect, the present invention provides a photoconversion agent having a structure as shown in Formula I:

[0036]

[0037] The preparation method of the photoconversion agent comprises the following steps:

[0038] Dissolving the powder of the compound represented by formula I in a first solvent by heating, cooling and crystallizing, and collecting the solid;

[0039] The first solvent includes at least one of ethyl acetate, N-methyl-2-pyrrolidone, and acetone.

[0040] The present invention controls the crystal form of the compound by adjusting the solvent type, etc., adjusts the fluorescence quantum efficiency, and improves the ultraviolet resistance of the photoconversion agent.

[0041] The preparation method of the compound powder represented by Formula I is not limited, for example, it can be prepared by referring to the method described in the patent application with publication number CN116426227A. The XPRD pattern of the prepared compound powder is as follows: Figure 1 shown.

[0042] In a specific embodiment of the present invention, after heating and dissolving, the method further comprises: adding a second solvent and performing heat preservation treatment; the second solvent comprises at least one of water and acetonitrile.

[0043] After heating and dissolving in the first solvent, the second solvent is added to change the solvent system, promote the crystal transformation of the compound in the corresponding solvent system, improve the crystal stability, and enhance the UV resistance.

[0044] In one embodiment of the present invention, the first solvent is N-methyl-2-pyrrolidone, and the second solvent is water.

[0045] In another embodiment of the present invention, the first solvent is acetone and the second solvent is acetonitrile.

[0046] In a specific embodiment of the present invention, the ratio of the first solvent to the powder is (10-100) mL: 1 g.

[0047] The present invention further regulates the ratio of the first solvent to the powder within the above range to ensure that the crystals are fully precipitated while taking into account the degree of crystal transformation. When the amount of the first solvent is too high, it is difficult to form a hot saturated solution, and too few crystals are precipitated during the cooling process; when the amount of the first solvent is too small, it is difficult for the compound to achieve crystal transformation in the solvent. For example, in different embodiments, the ratio of the first solvent to the powder can be 10mL﹕1g, 25mL﹕1g, 40mL﹕1g, 60mL﹕1g, 80mL﹕1g, 100mL﹕1g or a range consisting of any two of them. It is understandable that here (10~100)mL﹕1g means that compared to 1g of compound powder, the amount of the first solvent can be 10~100mL, rather than limiting the amount of powder to 1g.

[0048] In a specific embodiment of the present invention, the volume ratio of the first solvent to the second solvent is 1:(1-10).

[0049] The crystal type is related to the volume ratio of the solvents. Regulating the volume ratio of the first solvent to the second solvent within the above range is more conducive to achieving the desired crystal transformation and ensuring stability. For example, in different embodiments, the volume ratio of the first solvent to the second solvent can be 1:1, 1:3, 1:5, 1:8, 1:10 or a range consisting of any two of them.

[0050] In a specific embodiment of the present invention, during heating and dissolving, the temperature is 55-85° C. For example, in different embodiments, the temperature of heating and dissolving can be 55° C., 60° C., 65° C., 70° C., 75° C., 80° C., 85° C., or any two thereof.

[0051] In a specific embodiment of the present invention, during the heat preservation treatment, the temperature is 55-85°C and the time is 3-5h. For example, in different embodiments, the temperature of the heat preservation treatment can be 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or a range composed of any two thereof, and the time can be 3h, 3.5h, 4h, 4.5h, 5h or a range composed of any two thereof.

[0052] In a specific embodiment of the present invention, cooling and crystallizing includes: cooling to -15 to 15° C. For example, in different embodiments, cooling and crystallizing can be performed to -15° C., -10° C., -5° C., 0° C., 5° C., 10° C., 15° C., or any two thereof.

[0053] In actual operation, during the cooling and crystallization, the cooling method can be adjusted according to actual needs. It can be directly placed in a refrigeration device at a corresponding temperature for cooling, or placed in a gradient cooling device for cooling at a certain cooling rate, wherein the cooling rate can be 0.5-6°C / min, but is not limited thereto. After dropping to the preset temperature, it can be maintained for a period of time, such as 1-12 hours, to fully crystallize.

[0054] Another aspect of the present invention provides a packaging adhesive film, comprising a film body and any one of the above-mentioned photoconversion agents dispersed in the film body.

[0055] The photoconversion agent of the present invention has high fluorescence quantum efficiency and excellent ultraviolet resistance, and can be directly used for preparing packaging adhesive films without further modification treatment, thereby reducing the modification process.

[0056] In a specific embodiment of the present invention, the content of the photoconversion agent in the packaging film is 0.01% to 0.55%. For example, in different embodiments, the content of the photoconversion agent in the packaging film can be 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.4%, 0.5%, 0.55% or a range consisting of any two thereof, preferably 0.05% to 0.55%.

[0057] In a specific embodiment of the present invention, the film body includes the following components by weight: 100 parts of base resin, 0.5-1.5 parts of cross-linking agent, 0.1-1 parts of auxiliary cross-linking agent, 0.1-0.5 parts of antioxidant, 0.1-1 parts of light stabilizer and 0.3-1.5 parts of coupling agent.

[0058] The composition of the film body can be the same as that of the EVA film or POE film conventionally used for packaging films, and will not be described in detail here.

[0059] Among them, the types of crosslinking agent, auxiliary crosslinking agent, antioxidant, light stabilizer and coupling agent can be adjusted and selected according to the types used in conventional EVA film or POE film, as shown below, but not limited to. For example, the crosslinking agent can be selected from at least one of peroxide crosslinking agents, the auxiliary crosslinking agent can include ethylene glycol dimethacrylate, the antioxidant can include at least one of hindered phenol antioxidants and phosphite antioxidants, the light stabilizer can include 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, and the coupling agent can include at least one of silane coupling agents, such as epoxy-containing silane coupling agents.

[0060] In a specific embodiment of the present invention, the base resin includes EVA resin or POE resin.

[0061] The packaging film of the present invention can be prepared according to a conventional packaging film method. For example, the specific preparation method may include: mixing ingredients according to the composition of the packaging film, and extruding and casting to form a film.

[0062] In actual operation, the temperature of extrusion casting can be 80-90°C.

[0063] The thickness of the packaging film of the present invention can be adjusted according to actual needs, for example, it can be 0.3-0.6 mm, but is not limited thereto.

[0064] Another aspect of the present invention provides a photovoltaic module, comprising any one of the above-mentioned packaging films.

[0065] In a specific embodiment of the present invention, the photovoltaic module further includes a HJT cell and glass, and the packaging film is disposed between the HJT cell and the glass.

[0066] Some of the product information used in the specific implementation of the present invention may be as follows, but is not limited thereto:

[0067] EVA resin: Sailbon V2825, melt index is 25g / 10min, VA content is 28%.

[0068] Example 1

[0069] This embodiment provides a method for preparing a packaging film, comprising the following steps:

[0070] 100 parts by weight of EVA resin were weighed and placed in a mixer, and then 1 part by weight of tert-butyl peroxycarbonate-2-ethylhexyl ester, 0.5 parts by weight of ethylene glycol dimethacrylate, 0.5 parts by weight of tris(nonylphenyl)phosphite, 0.6 parts by weight of 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 1.5 parts by weight of γ-glycidyloxypropyltrimethoxysilane and 0.1 parts by weight of a photoconverter were added into the mixer, the mixture was evenly mixed in the mixer, and the mixture was put into a casting machine, and an EVA encapsulation film with a thickness of 0.5 mm was prepared by plasticizing, extruding, stretching, pulling and winding at 80°C.

[0071] The preparation method of the photoconversion agent of this embodiment comprises the following steps:

[0072] The powder of the compound represented by Formula I is added to ethyl acetate, and then heated to about 75°C and refluxed until the compound is completely dissolved, and then cooled to -10°C at a cooling rate of 5°C / min, and allowed to stand for 5 hours for crystallization; the solid is collected by filtration, and then the solid is dried under reduced pressure at 65-66°C.

[0073] Wherein, the ratio of the compound powder represented by Formula I to ethyl acetate is 1 g: 30 mL.

[0074] The photoconversion agent prepared in this example was tested, and the XPRD diagram was as follows: Figure 2 shown.

[0075] Example 2

[0076] This embodiment refers to the preparation method of the encapsulation film of Embodiment 1, and the only difference is that the preparation method of the photoconversion agent is different.

[0077] The preparation method of the photoconversion agent of this embodiment comprises the following steps:

[0078] The powder of the compound represented by formula I is added to N-methyl-2-pyrrolidone, and then heated to 80°C and stirred to dissolve the compound. After that, water is added, and the mixture is kept at 80°C for 4 hours under stirring. Then, the mixture is cooled to 10°C at a cooling rate of 0.5°C / min, and allowed to stand for 12 hours for crystallization. The solid is collected by suction filtration, and then the solid is dried under reduced pressure at 65-66°C.

[0079] The ratio of the compound powder represented by Formula I to N-methyl-2-pyrrolidone is 1 g:50 mL; the volume ratio of water to N-methyl-2-pyrrolidone is 5:1.

[0080] The photoconversion agent prepared in this example was tested, and the XPRD diagram was as follows: Figure 3 shown.

[0081] Example 3

[0082] This embodiment refers to the preparation method of the encapsulation film of Embodiment 1, and the only difference is that the preparation method of the photoconversion agent is different.

[0083] The preparation method of the photoconversion agent of this embodiment comprises the following steps:

[0084] The powder of the compound represented by formula I is added to acetone, and then heated to about 60°C and stirred to dissolve the compound. Then, acetonitrile is added, and the mixture is kept at 60°C for 4 hours under stirring. Then, the mixture is cooled to -10°C at a cooling rate of 1°C / min, and allowed to stand for 8 hours for crystallization. The solid is collected by filtration, and then the solid is dried under reduced pressure at 65-66°C.

[0085] Wherein, the ratio of the compound powder represented by Formula I to acetone is 1 g:60 mL; the volume ratio of acetonitrile to acetone is 1:1.

[0086] The photoconversion agent prepared in this example was tested, and the XPRD diagram was as follows: Figure 4 shown.

[0087] Example 4

[0088] This embodiment refers to the preparation method of the encapsulation film of Embodiment 1, and the only difference is that the preparation method of the photoconversion agent is different.

[0089] The preparation method of the photoconversion agent of this embodiment comprises the following steps:

[0090] The powder of the compound represented by formula I is added to N-methyl-2-pyrrolidone, and then heated to 80°C and stirred to dissolve the compound. After that, water is added, and the mixture is kept at 80°C for 4 hours under stirring. Then, the mixture is cooled to -10°C at a cooling rate of 5°C / min, and allowed to stand for 3 hours for crystallization. The solid is collected by suction, and then the solid is dried under reduced pressure at 65-66°C.

[0091] The ratio of the compound powder represented by Formula I to N-methyl-2-pyrrolidone is 1 g:50 mL; the volume ratio of water to N-methyl-2-pyrrolidone is 5:1.

[0092] The photoconversion agent prepared in this example was tested, and the XPRD diagram was as follows: Figure 5 shown.

[0093] Example 5

[0094] This embodiment refers to the preparation method of the encapsulation film of Embodiment 1, and the only difference is that the preparation method of the photoconversion agent is different.

[0095] The photoconversion agent of this embodiment is prepared by referring to the photoconversion agent of embodiment 2, except that the amount of N-methyl-2-pyrrolidone and water used is different.

[0096] In this embodiment, the ratio of the powder of the compound represented by Formula I to N-methyl-2-pyrrolidone is 1 g:10 mL; and the volume ratio of water to N-methyl-2-pyrrolidone is 1:1.

[0097] Example 6

[0098] This embodiment refers to the preparation method of the encapsulation film of Embodiment 1, and the only difference is that the preparation method of the photoconversion agent is different.

[0099] The photoconversion agent of this embodiment is prepared by referring to the photoconversion agent of embodiment 2, except that the amount of N-methyl-2-pyrrolidone and water used is different.

[0100] In this embodiment, the ratio of the compound powder represented by Formula I to N-methyl-2-pyrrolidone is 1 g:100 mL; the volume ratio of water to N-methyl-2-pyrrolidone is 10:1.

[0101] Example 7

[0102] This embodiment refers to the preparation method of the encapsulation film of Embodiment 1, and the only difference is that the preparation method of the photoconversion agent is different.

[0103] The photoconversion agent of this embodiment is prepared by referring to the photoconversion agent of embodiment 2, except that the amount of N-methyl-2-pyrrolidone and water used is different.

[0104] In this embodiment, the ratio of the compound powder represented by Formula I to N-methyl-2-pyrrolidone is 1 g:200 mL; the volume ratio of water to N-methyl-2-pyrrolidone is 15:1.

[0105] Example 8

[0106] This embodiment refers to the preparation method of the encapsulation film of Embodiment 2, the only difference being that the amount of the photoconversion agent used is different.

[0107] The amount of the photoconversion agent used in this embodiment is 0.012 parts by weight.

[0108] Example 9

[0109] This embodiment refers to the preparation method of the encapsulation film of Embodiment 2, the only difference being that the amount of the photoconversion agent used is different.

[0110] The amount of the photoconversion agent used in this embodiment is 5 parts by weight.

[0111] Comparative Example 1

[0112] Comparative Example 1 refers to the method for preparing the encapsulation film of Example 1, except that no photoconversion agent is added.

[0113] Comparative Example 2

[0114] Comparative Example 2 refers to the method for preparing the encapsulation film of Example 1, except that an equal weight of the compound powder represented by Formula I (untreated) is used to replace the photoconversion agent prepared in Example 1.

[0115] Comparative Example 3

[0116] Comparative Example 3 refers to the preparation method of the encapsulation film of Example 1, except that the preparation method of the photoconversion agent is different.

[0117] The photoconversion agent of Comparative Example 3 is prepared by referring to the photoconversion agent of Example 2, except that an equal volume of ethanol is used to replace N-methyl-2-pyrrolidone.

[0118] Experimental Example 1

[0119] The fluorescence quantum efficiency of the photoconversion agents of different embodiments and comparative examples was tested under the same test conditions. The test results are shown in Table 1.

[0120] Table 1 Fluorescence quantum efficiency of different photoconversion agents

[0121]

[0122]

[0123] Experimental Example 2

[0124] In order to compare and illustrate the performance differences of the encapsulation films of different embodiments and comparative examples, the encapsulation films of different embodiments and comparative examples were respectively made into photovoltaic module samples to be tested, and the initial module power and the photovoltaic module power after UV120kWh of different photovoltaic modules were tested with reference to IEC61215. The test results are shown in Table 2.

[0125] The preparation of the photovoltaic module sample to be tested includes: an upper glass, an upper packaging film, a battery cell, a lower packaging film, and a lower glass, all of which are double-glass modules. The upper packaging film and the lower packaging film are both packaging films prepared in various embodiments or comparative examples of the present invention, wherein the battery cell adopts a 210 size HJT battery cell, and finally a 110 version module is made.

[0126] Table 2 Performance test results of photovoltaic modules corresponding to different encapsulation films

[0127] serial number Initial module power (W) UV120kWh after module power (W) Example 1 594.3 590.2 Example 2 601.9 599.6 Example 3 597.4 594.6 Example 4 600.8 598.5 Example 5 599.5 597.1 Example 6 598.4 585.8 Example 7 595.7 591.7 Example 8 586.4 561.8 Example 9 601.4 601.1 Comparative Example 1 585.5 561.7 Comparative Example 2 590.6 582.3 Comparative Example 3 591.7 584.2

[0128] From the above test results, it can be seen that the packaging film of the present invention, by directly using the photoconversion agent of the present invention therein without the need for additional compounding processing steps, can not only significantly improve the power of the component, but also has excellent UV stability, can extend the service life of the packaging film, and can also reduce the power attenuation of the component.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photoconversion agent, characterized in that: Having the structure shown in Formula I: The preparation method of the photoconversion agent comprises the following steps: heating and dissolving the compound powder represented by formula I in a first solvent, cooling and crystallizing, and collecting the solid; The first solvent includes at least one of ethyl acetate, N-methyl-2-pyrrolidone and acetone.

2. The photoconversion agent according to claim 1, characterized in that: After the heating and dissolving, the method further comprises: adding a second solvent for heat preservation treatment; the second solvent comprises at least one of water and acetonitrile.

3. The photoconversion agent according to claim 1, characterized in that: The ratio of the first solvent to the powder is (10-100) mL: 1 g.

4. The photoconversion agent according to claim 2, characterized in that: The volume ratio of the first solvent to the second solvent is 1:(1-10).

5. The photoconversion agent according to claim 1, characterized in that: During the heating and dissolving, the temperature is 55-85°C.

6. The photoconversion agent according to claim 2, characterized in that: During the heat preservation treatment, the temperature is 55 to 85° C. and the time is 3 to 5 hours.

7. The photoconversion agent according to claim 1, characterized in that: The temperature reduction crystallization comprises: cooling to -15 to 15°C.

8. A packaging film, characterized in that: The invention comprises a film body and the photoconversion agent according to any one of claims 1 to 7 dispersed in the film body.

9. The packaging film according to claim 8, characterized in that: In the packaging film, the content of the light conversion agent is 0.01% to 0.55%.

10. A photovoltaic module, characterized in that: Comprising the encapsulation film according to claim 8 or 9.

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