A tunable, passive refrigeration photovoltaic module

Abstract

The present application relates to the technical field of photovoltaic modules, and provides a tunable passive refrigeration photovoltaic module, which comprises a passive radiation refrigeration layer, one or more sub-layers of which are stacked, at least one of the sub-layers in the passive radiation refrigeration layer being a radiation refrigeration function sub-layer; a photovoltaic cell unit layer; an encapsulation layer, which comprises a base resin and a filler doped in the base resin; the passive radiation refrigeration layer, the photovoltaic cell unit layer and the encapsulation layer are sequentially stacked from top to bottom and connected with each other. The above configuration radiates the heat inside the photovoltaic module outward through the radiation refrigeration function without additional energy consumption, so as to reduce the temperature of the photovoltaic module. Meanwhile, the encapsulation layer can efficiently reflect light of a specific spectrum, so that the color appearance of the photovoltaic module can be realized without increasing the temperature rise, and the utilization efficiency of light and the photoelectric conversion efficiency of the cell are further improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic module technology, and in particular to a color-tunable passive cooling photovoltaic module. Background Technology

[0002] The operating temperature of photovoltaic modules is a core parameter affecting their power generation efficiency and long-term reliability. Excessively high operating temperatures not only lead to power loss in the cells but also accelerate the aging of encapsulation materials and the degradation of cell performance. To control temperature rise, the industry commonly uses high-reflectivity encapsulation films. This technology enhances the reflection of near-infrared wavelengths of sunlight by incorporating high-reflectivity fillers into matrix resins such as ethylene vinyl acetate (EVA) or polyolefin elastomer (POE), thereby reducing heat input and achieving module cooling and power increase. However, this technical approach can only produce a single white or black encapsulation film, severely limiting its color performance.

[0003] The market demand for colored modules, such as those for building-integrated photovoltaics (BIPV), is growing. However, simply adding traditional pigments for coloring can cause the modules to heat up further due to the heat absorption of the pigments, which contradicts the goal of cooling. Therefore, existing technologies struggle to achieve a variety of module colors while maintaining effective cooling.

[0004] Passive radiative cooling is a technology that uses the broadband radiation from the material surface into outer space (approximately 3K) to spontaneously dissipate heat without external energy input. High-performance daytime radiative cooling materials must simultaneously meet two key optical characteristics: first, high reflectivity in the 0.25–2.5 μm solar spectral region to reduce solar radiation absorption; and second, high emissivity in the 8–13 μm atmospheric transparency window region to enable the material to effectively dissipate its own heat through infrared radiation. How to apply the principle of passive radiative cooling to the photovoltaic packaging field, achieving passive cooling while imparting the desired color to the module, has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] This invention provides a color-tunable passive cooling photovoltaic module to solve the problem that existing photovoltaic modules are unable to achieve both color diversity and effective cooling, resulting in limited power generation efficiency.

[0006] To achieve the above objectives, according to one aspect of the present invention, a color-tunable passively cooled photovoltaic module is provided, comprising: The passive radiation cooling layer is composed of one or more layers stacked together, and at least one layer in the passive radiation cooling layer is a radiation cooling functional layer. Photovoltaic cell unit layer; An encapsulation layer, the encapsulation layer comprising a matrix resin and fillers doped in the matrix resin; The passive radiation cooling layer, photovoltaic cell unit layer, and encapsulation layer are stacked sequentially from top to bottom and connected to each other.

[0007] According to the color-tunable passively cooled photovoltaic module provided by the present invention, the emissivity of the passive radiation cooling layer is ≥90% in the 8µm~13µm band.

[0008] According to the color-tunable passively cooled photovoltaic module provided by the present invention, the material of the radiation cooling functional layer in the passive radiation cooling layer is selected from at least one of the following substances: TPU, PVDF and PMMA resin.

[0009] According to the color-tunable passively cooled photovoltaic module provided by the present invention, the passive radiative cooling layer further includes one or more encapsulation functional layers, which are stacked above and / or below the radiative cooling functional layers.

[0010] The color-tunable passively cooled photovoltaic module provided by the present invention has an encapsulation functional layer of EVA or POE.

[0011] The color-tunable passively cooled photovoltaic module provided by the present invention has a single-layer encapsulation layer; and / or, the filler includes color-tuning filler and / or reflective filler.

[0012] The color-tunable passively cooled photovoltaic module provided by the present invention includes, but is not limited to, SiO2, TiO2, Al2O3 photonic crystals, and / or, the reflective filler includes, but is not limited to, Y2O3, TiO2 nanosheets.

[0013] According to the color-tunable passive cooling photovoltaic module provided by the present invention, the mass fraction of the color-tuning filler in the encapsulation layer is 0.5wt%~10wt%, and / or the mass fraction of the reflective filler in the encapsulation layer is 0.5wt%~5wt%.

[0014] The color-tunable passive cooling photovoltaic module provided by the present invention has a D50 particle size range of 50nm~800nm ​​for the reflective filler.

[0015] The color-tunable passively cooled photovoltaic module provided by the present invention further includes a cover glass and a back sheet, wherein the cover glass is stacked above the passively radiative cooling layer and connected to each other, and the back sheet is stacked below the encapsulation layer and connected to each other.

[0016] The color-tunable passively cooled photovoltaic module provided by this invention radiates heat to the outside of the photovoltaic module in a layered manner through a radiative cooling function. This reduces its own temperature without consuming electricity or other forms of energy, ultimately providing cooling for the photovoltaic cell units. This keeps the photovoltaic cell units at a suitable temperature level to improve power generation efficiency and extend the lifespan of the photovoltaic cell units. Furthermore, the color-tunable passively cooled photovoltaic module of this invention incorporates filler doping into the encapsulation layer located below the photovoltaic cell units, giving it high reflectivity for light within a specific spectral range. This not only produces vibrant colors but also reflects light within that specific spectral range back to the photovoltaic cell units, thereby improving the light utilization rate and photoelectric conversion efficiency of the photovoltaic cell units. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the color-tunable passively cooled photovoltaic module provided by the present invention.

[0019] Figure label: 1. Passive radiative cooling layer; 11. Encapsulation functional layer; 12. Radiative cooling functional layer; 13. Encapsulation functional layer; 2. Photovoltaic cell unit layer; 3. Encapsulation layer; 31. Matrix resin; 32. Filler; 4. Cover glass; 5. Backplate. Detailed Implementation

[0020] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but should not be used to limit the scope of this application.

[0021] In the description of the embodiments of this application, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections, wherein a fixed connection can include an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0023] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0025] The following is combined Figure 1 This invention describes a color-tunable passively cooled photovoltaic module.

[0026] like Figure 1As shown, the color-tunable passively cooled photovoltaic module provided by the present invention includes at least a passive radiative cooling layer 1, a photovoltaic cell unit layer 2, and an encapsulation layer 3. The passive radiative cooling layer 1, the photovoltaic cell unit layer 2, and the encapsulation layer 3 are stacked sequentially from top to bottom and connected to each other. For example, the passive radiative cooling layer 1 is connected to the photovoltaic cell unit layer 2, and the photovoltaic cell unit layer 2 is connected to the encapsulation layer 3. The term "passive cooling" indicates that the color-tunable passively cooled photovoltaic module of the present invention, especially the passive radiative cooling layer 1, can reduce its own temperature and that of the photovoltaic cell unit layer 2 without consuming electrical energy or other forms of energy. That is, this cooling method is passive and continuous, rather than relying on some active control method.

[0027] The passive radiative cooling layer 1 is composed of one or more layers stacked together. In particular, when the passive radiative cooling layer 1 is composed of multiple layers stacked together, the layers are stacked sequentially and then formed into an integral laminate by means of a co-extrusion molding process. At least one layer in the passive radiative cooling layer 1 is a radiative cooling functional layer 12. In other words, when the passive radiative cooling layer 1 is composed of only a single layer, that single layer is the radiative cooling functional layer 12; while when the passive radiative cooling layer 1 is composed of multiple layers, at least one of them needs to be set as the radiative cooling functional layer 12.

[0028] The encapsulation layer 3 is a single-layer structure. Furthermore, the encapsulation layer 3 includes a matrix resin 31 and a filler 32 doped into the matrix resin 31. The filler 32 enables the encapsulation layer 3 to have high reflectivity to light within a specific spectral range.

[0029] The photovoltaic cell unit layer 2 is sandwiched between the passive radiation cooling layer 1 and the encapsulation layer 3. It can receive direct sunlight from above and light reflected back from the encapsulation layer 3 (and the backsheet 5) below. Thus, under the same ambient illuminance, the photovoltaic cell unit layer 2 receives light on both sides simultaneously, so as to absorb as much sunlight as possible and convert it into electrical energy.

[0030] With the above configuration, the radiative cooling layer 12 radiates heat to the outside of the photovoltaic module at all times, so as to reduce the temperature of the photovoltaic module without consuming electrical energy or other forms of energy. This keeps the photovoltaic cell unit layer 2 at a suitable temperature level to improve power generation efficiency. At the same time, by filling the encapsulation layer 3 32 located below the photovoltaic cell unit layer 2 with filler 32, it is made to have high reflectivity to light in a specific spectral range. This allows for the colorization of the photovoltaic module without causing a significant increase in the temperature of the photovoltaic module, and improves the light utilization rate and photoelectric conversion efficiency of the photovoltaic cell unit.

[0031] Furthermore, the radiative cooling functional layer 12 is composed of a material with high emissivity in the infrared band. Here, the term "infrared band" preferably refers to the infrared light band of 8µm to 13µm. The aforementioned material radiates heat to the outside through the infrared atmospheric window (i.e., the infrared light band of 8µm to 13µm), thereby reducing the surface temperature of the object to below the ambient temperature. As the name suggests, in one embodiment of this application, the radiative cooling functional layer 12 is substantially composed of such a material without the need for modification by adding other components or coating its surface.

[0032] Therefore, the material suitable for constituting the radiative cooling functional layer 12 may be selected from at least one of the following materials: thermoplastic polyurethane (TPU), poly(methyl methacrylate) (PMMA), polydimethylsiloxane, polyvinylidene fluoride (PVDF), polylactic acid (PLA), polyformaldehyde (POM), polytetrafluoroethylene (PTFE), or similar materials.

[0033] Furthermore, the passive radiative cooling layer 1 also includes one or more encapsulation functional layers 11 and 13, which are stacked above and / or below the radiative cooling functional layer 12. For example, a single encapsulation functional layer 11 can be provided above the radiative cooling functional layer 12, or a single encapsulation functional layer 13 can be provided below it; or, encapsulation functional layers 11 and 13 can be provided on both sides of the radiative cooling functional layer 12.

[0034] The materials used for the encapsulation functional layers 11 and 13 can be selected from at least one of the following: EVA, POE, or similar materials. At least one side surface of the passive radiative cooling functional layer 12 is covered by the encapsulation functional layers 11 and 13, which ensures the adhesion performance of the encapsulant film (i.e., the passive radiative cooling layer 1) to the photovoltaic cell unit layer 2, prevents the occurrence of bubbles and delamination, and further improves the stability of the performance of each functional layer.

[0035] In addition, for the encapsulation layer 3, the matrix resin 31 may be selected from at least one of the following materials: EVA, POE or similar materials.

[0036] Furthermore, according to mass fraction, the encapsulation layer 3 and the encapsulation functional layers 11 and 13 each independently include 0.05%~2% of crosslinking agent, 0.05%~3% of co-crosslinking agent and 0.1%~3% of silane coupling agent. The crosslinking agent is selected from any one or more of tert-butyl peroxycarbonate, dicumyl peroxide, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, azobisisobutyronitrile, and benzoyl peroxide; the co-crosslinking agent is selected from any one or more of trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxylate, and trimethylolpropane tetraacrylate; the silane coupling agent is selected from any one or more of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltriterperoxytert-butylsilane, vinyltriacetoxysilane, vinyltri(β-methoxyethoxy)silane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, and vinyltriethoxysilane. The presence of the aforementioned crosslinking agents and co-crosslinking agents helps to accelerate the crosslinking speed of the film, shorten the time and temperature required for crosslinking, and form a more uniform and stable crosslinking network, which helps to improve the mechanical strength and weather resistance of the film; the addition of silane coupling agents helps to enhance interfacial adhesion and further improve the weather resistance of the film.

[0037] In addition, one type of filler 32 doped in the matrix resin 31 is a reflective filler, which is used to give the matrix resin 31 high reflectivity. Another type of filler 32 doped in the matrix resin 31 is a color-tuning filler. In a wide range of light spectrum, the color-tuning filler has different refractive indices for light in different spectral ranges, and selectively reflects light in specific wavelength bands, thereby presenting different colors.

[0038] A particularly advantageous feature is that reflective fillers and color-tuning fillers can be used in combination. Based on this, the color-tuning filler can scatter light of a specific spectral range from the broad-field light and, with the help of the reflective filler, reflect it back to the photovoltaic cell layer 2 with a relatively high reflectivity. By combining reflective and color-tuning fillers, the photovoltaic cell layer 2 can receive more reflected light of the specific spectral range, thereby improving the power generation efficiency of the photovoltaic cell layer 2.

[0039] Furthermore, the color-correcting filler includes, but is not limited to, SiO2, TiO2, and Al2O3 photonic crystals.

[0040] This type of photonic crystal exhibits a periodically varying refractive index distribution in space, enabling the formation of photonic band gaps. It selectively reflects light in specific wavelengths, resulting in vibrant structural colors that dynamically change with the viewing angle. Since the color development mechanism originates from physical interference rather than chemical absorption, this filler itself does not readily absorb light energy and convert it into heat. This significantly reduces the component temperature rise caused by the heat absorption of traditional pigments, lowering the component temperature and improving component efficiency. Simultaneously, its high reflectivity and high interference efficiency allow for high-saturation coloring with low addition amounts while maintaining the physicochemical stability of the matrix material.

[0041] Furthermore, the reflective filler includes, but is not limited to, Y2O3 and TiO2 nanosheets. These two-dimensional nanosheets possess high specific surface area and a regular layered structure, and can synergize with photonic crystals to form a highly efficient, broad-spectrum reflective layer in the 400nm~1100nm wavelength range, significantly blocking light in this wavelength range from passing through the encapsulation layer into the backsheet. On one hand, this reflects a large amount of originally lost useful light back to the surface of the photovoltaic cell unit layer 2, promoting its reabsorption and utilization, thereby improving the photoelectric conversion efficiency and output power of the photovoltaic module. On the other hand, by blocking light absorption by non-power generation structures such as the backsheet 5, it effectively suppresses unnecessary temperature rise in the photovoltaic module, reduces heat load and heat loss, and is beneficial to maintaining the long-term operational stability and power generation performance of the module.

[0042] Furthermore, the toning filler in the encapsulation layer 3 has a mass fraction of 0.5wt% to 10wt%. And / or, the reflective filler in the encapsulation layer 3 has a mass fraction of 0.5wt% to 5wt%. The advantage of this configuration is that, compared with the prior art, such as patent CN119119737A, the amount of filler 32 required for this encapsulation layer 3 is much lower than the doping amount of the prior art, which can significantly reduce production costs in the context of mass production.

[0043] Furthermore, the reflective filler is a two-dimensional nanosheet with a D50 particle size ranging from 50 nm to 800 nm, preferably from 50 nm to 500 nm. This preferred range aims to ensure uniform dispersion of the filler: excessively large particle size can easily lead to sedimentation and agglomeration, affecting the uniformity of dispersion; excessively small particle size will increase the difficulty and cost of the dispersion process.

[0044] Furthermore, the color-tunable passively cooled photovoltaic module may also include a cover glass 4 and a back sheet 5. The cover glass 4 is stacked on top of the passive radiative cooling layer 1 and connected to each other; while the back sheet 5 is stacked on the bottom of the encapsulation layer 3 and connected to each other.

[0045] The advantage of this configuration is that the cover glass 4 and backsheet 5, as standard configurations for photovoltaic modules, each protect the functional components within the photovoltaic module (i.e., the passive radiative cooling layer 1, the photovoltaic cell layer 2, and the encapsulation layer 3) on both sides. Specifically, the cover glass 4 is typically used to protect the functional components from damage caused by foreign objects, prevent rain, snow, and dust from entering and accumulating inside the photovoltaic module, and so on; the backsheet 5 is typically used to determine whether the photovoltaic module is unidirectional or bidirectional, that is, whether the backsheet 5 itself is translucent, so as to be configured according to the specific photovoltaic power generation environment, thereby improving the power generation efficiency of the photovoltaic module and even the entire power generation plant.

[0046] Furthermore, for the passive radiative cooling layer 1, in the case of its three-layer structure, namely the encapsulation functional layer 11, the radiative cooling functional layer 12, and the encapsulation functional layer 13, the thickness of the encapsulation functional layers 11 and 13 can be designed to be 0.1mm to 0.3mm, and the thickness of the radiative cooling functional layer 12 can be designed to be 20µm to 60µm.

[0047] On the other hand, the thickness of the encapsulation layer 3 can be designed to be 10µm to 50µm. Therefore, the macroscopic dimensions of the passive radiative cooling layer 1 and the encapsulation layer 3 can be made quite small, having little impact on the volume and weight of the photovoltaic module.

[0048] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0049] All raw materials used in the embodiments of this application are existing technologies and can be purchased.

[0050] Example 1 This embodiment provides a color-tunable passively cooled photovoltaic module, wherein the passive radiation cooling layer 1 is formed as a three-layer composite structure.

[0051] For the passive radiative cooling layer 1, the middle layer is the radiative cooling functional layer 12. By mass fraction, the radiative cooling functional layer 12 is composed of 100% TPU. The encapsulation functional layers 11 and 13 located on either side of the radiative cooling functional layer 12 are composed of EVA. By mass fraction, the encapsulation functional layers 11 and 13 respectively comprise 98.5% EVA, 0.5% tert-butyl peroxycarbonate, 0.5% triallyl cyanurate, and 0.5% vinyltriethoxysilane.

[0052] The passive radiation cooling layer 1 is prepared by: forming an integrated laminate through a co-extrusion molding process; then, cooling the laminate and winding it up to obtain the passive radiation cooling layer 1. The thickness of the encapsulation functional layers 11 and 13 is 0.2 mm, and the thickness of the radiation cooling functional layer 12 is 50 µm.

[0053] By mass fraction, encapsulation layer 3 comprises 93.5% EVA, 3.5% SiO2 photonic crystal (D50 particle size of 200 nm), 1.5% Y2O3 nanosheets, 0.5% tert-butyl peroxycarbonate, 0.5% triallyl cyanurate, and 0.5% vinyltriethoxysilane. The D50 particle size of the Y2O3 nanosheets is 400 nm. The preparation method involves mixing the above-mentioned raw materials by mass fraction and then melt-extruding to obtain encapsulation layer 3.

[0054] Preparation method of color-tunable passively cooled photovoltaic module: Place back sheet 5, encapsulation layer 3, photovoltaic cell unit layer 2, passive radiation cooling layer 1 and cover glass 4 in sequence from bottom to top; move the above assembly to a laminator for lamination, and the lamination conditions are: lamination temperature set to 145℃, lamination pressure set to 0.1MPa, and lamination process time set to 16min.

[0055] Example 2 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the encapsulation functional layers 11 and 13 are composed of POE.

[0056] Based on mass fraction, the encapsulation functional layers 11 and 13 comprise 98.5% POE, 0.5% tert-butyl peroxycarbonate isopropyl, 0.5% triallyl cyanurate, and 0.5% vinyltriethoxysilane, respectively.

[0057] Example 3 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the radiative cooling functional layer 12 is composed of 100% PMMA.

[0058] Example 4 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the passive radiation cooling layer 1 is formed as a single-layer structure, which is composed of 100% TPU.

[0059] Example 5 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the filler of the encapsulation layer 3 contains only SiO2 photonic crystals.

[0060] By mass fraction, encapsulation layer 3 comprises 95% EVA, 3.5% SiO2 photonic crystal (D50 particle size of 200 nm), 0.5% tert-butyl peroxycarbonate isopropyl, 0.5% triallyl cyanurate, and 0.5% vinyltriethoxysilane. It is prepared by mixing the above-mentioned raw materials by mass fraction and then melt-extruding to obtain encapsulation layer 3.

[0061] Example 6 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the filler in the encapsulation layer 3 contains only Y2O3 nanosheets.

[0062] By mass fraction, encapsulation layer 3 comprises 97% EVA, 1.5% Y₂O₃ nanosheets, 0.5% tert-butyl peroxycarbonate isopropyl, 0.5% triallyl cyanurate, and 0.5% vinyltriethoxysilane. The D50 particle size of the Y₂O₃ nanosheets is 400 nm. The preparation method involves mixing the above-mentioned raw materials by mass fraction and then melt-extruding to obtain a transparent encapsulation layer 3.

[0063] Example 7 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the SiO2 photonic crystal is replaced with a TiO2 photonic crystal (D50 particle size is 200nm).

[0064] Example 8 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that Y2O3 nanosheets are replaced with TiO2 nanosheets with a D50 particle size of 400nm.

[0065] Example 9 This embodiment provides a color-tunable passively cooled photovoltaic module, differing from Embodiment 1 only in that: by mass fraction, the encapsulation layer 3 comprises 97.5% EVA, 0.5% SiO2 photonic crystal (D50 particle size of 240nm), 0.5% Y2O3 nanosheets, 0.5% tert-butyl peroxycarbonate isopropyl, 0.5% triallyl cyanurate, and 0.5% vinyltriethoxysilane. The D50 particle size of the Y2O3 nanosheets is 400nm. The preparation method involves mixing the above-mentioned raw materials by mass fraction and then melt-extruding to obtain the encapsulation layer 3.

[0066] Example 10 This embodiment provides a color-tunable passively cooled photovoltaic module, differing from Embodiment 1 only in that: by mass fraction, the encapsulation layer 3 comprises 83.5% EVA, 10% SiO2 photonic crystal (D50 particle size of 300nm), 5% Y2O3 nanosheets, 0.5% tert-butyl peroxyisopropyl carbonate, 0.5% triallyl cyanurate, and 0.5% vinyltriethoxysilane. The D50 particle size of the Y2O3 nanosheets is 400nm. The preparation method involves mixing the above-mentioned raw materials by mass fraction and then melt-extruding to obtain the encapsulation layer 3.

[0067] Example 11 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the D50 particle size of the Y2O3 nanosheets is 50nm.

[0068] Example 12 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the D50 particle size of the Y2O3 nanosheets is 300nm.

[0069] Example 13 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the D50 particle size of the Y2O3 nanosheets is 500nm.

[0070] Example 14 This embodiment provides a color-tunable passively cooled photovoltaic module, which differs from Embodiment 1 only in that the D50 particle size of the Y2O3 nanosheets is 800nm.

[0071] Comparative Example 1 The difference from Example 1 is that the encapsulation functional layer 11 of Example 1 is used instead of the passive radiation cooling layer 1.

[0072] Comparative Example 2 The difference from Example 1 is that the addition of SiO2 photonic crystal and Y2O3 nanosheets to the encapsulation layer 3 is omitted.

[0073] Comparative Example 3 The difference from Example 1 is that the encapsulation functional layer 11 of Example 1 is used to replace the passive radiation cooling layer 1 and the filler in the encapsulation layer 3 is removed.

[0074] By mass fraction, encapsulation layer 3 comprises 98.5% EVA, 0.5% tert-butyl peroxycarbonate isopropyl, 0.5% triallyl cyanurate, and 0.5% vinyltriethoxysilane. It is prepared by mixing the above-mentioned raw materials by mass fraction and then melt-extruding to obtain encapsulation layer 3.

[0075] Performance testing The transmittance and emissivity of the passive radiation cooling layer 1 prepared according to Examples 1-14 and Comparative Examples 1-3, and the reflectivity of the encapsulation layer 3 were tested, wherein: The transmittance test method refers to test method 5.5.1.3 in standard GB / T 29848 "Ethylene-vinyl acetate copolymer (EVA) film for photovoltaic module encapsulation": The samples are tested according to the spectrophotometer method of GB / T 2410-2008. The wavelength range of the spectrophotometer is set to 380nm~1100nm. At least three samples are tested in each group, and the average value of the test results is taken. The transmittance of passive radiative cooling layer 1 is tested separately. The emissivity was measured using a Fourier transform infrared spectrometer equipped with a gold-plated integrating sphere to test the infrared emissivity of the passive radiative cooling layer 1. The infrared spectrum was measured in the range of 400–4000 cm⁻¹. -1 (Wavenumber and wavelength are reciprocals of each other, i.e., 2.5 µm to 14 µm), and the test results range from 8 µm to 13 µm; The reflectance test method refers to test method 5.5.2.3 in standard GB / T 29848 "Ethylene-vinyl acetate copolymer (EVA) film for photovoltaic module encapsulation": The sample is tested according to the spectrophotometric method of ASTM E 424-71 (2015). The wavelength range of the spectrophotometer is set to 400nm~1100nm, and the reflectance of encapsulation layer 3 is tested separately.

[0076] Furthermore, the internal temperature of the photovoltaic modules, their appearance after 1000 hours of damp heat aging, and their power output were tested. All tested modules were 300mm x 300mm in size, and the second layer of the photovoltaic cell unit used Jinko Solar's TOPCon cells. The test method for the internal temperature rise of the module is as follows: Before laminating the module, the temperature measuring end of the PT100 / T type thermocouple is attached to the non-grid area of ​​the photovoltaic cell unit layer 2 with high thermal conductivity adhesive (thermal conductive silicone), and the lead wire is led out from the edge of the module to avoid damaging the thermocouple during lamination; the module is manufactured according to the normal lamination and encapsulation process, ensuring that there are no air bubbles or delamination at the pre-embedded area, and that the thermocouple is tightly attached to the photovoltaic cell unit layer 2; the module is placed in a solar simulator, and the standard irradiance (1000W / ㎡, AM1.5G) and ambient temperature (25℃) are set; according to the test requirements, the module is connected to an electronic load, adjusted to the maximum power point state, and stabilized for more than 30 minutes (ensuring that the module temperature reaches thermal equilibrium, i.e., temperature change ≤0.1℃ / min), and then the internal temperature of the module is measured; The test method for the appearance of the components after damp heat aging shall be carried out in accordance with the test method of GB / T2423.3; The component power test method shall be in accordance with IEC TS 2804-1: 2015.

[0077] In addition, the testing method of the photovoltaic module Lab refers to the GB / T 3979-2008 test standard. The encapsulant film is cut into 10cm×10cm pieces, placed between two release films and laminated. The L, a, and b values ​​of the encapsulant film are tested in transmission mode. Five points are tested for each sample, and three samples are tested and the average value is taken.

[0078] The results of the above tests are shown in Table 1 below: Table 1

[0079] According to the test results, the photovoltaic module in this embodiment has an emissivity of ≥90% in the infrared atmospheric window (i.e., the 8 µm~13 µm band) for its passive radiative cooling layer 1. This indicates that the layer can efficiently dissipate the module's heat to the atmosphere in the form of infrared radiation without relying on external energy input. The encapsulation layer 3 has high reflectivity and can achieve module colorization by introducing specific color fillers. The color fillers selected in this application avoid the problem of module temperature rise caused by heat absorption in traditional pigments. While reflecting more incident light, they do not increase heat absorption, which is beneficial for the selective utilization of light energy by the cells, thereby improving the photoelectric conversion efficiency of the module.

[0080] Of particular note is that the passive radiation cooling layer 1 and the encapsulation layer 3 work synergistically to achieve color control of the photovoltaic module while passively reducing the module's operating temperature, increasing output power, and maintaining excellent light transmittance and aging resistance. Experimental data show that the photovoltaic module prepared according to the embodiment is significantly superior to the comparative photovoltaic module in terms of internal temperature and output power.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A color-tunable passively cooled photovoltaic module, characterized in that, include: A passive radiative cooling layer is composed of one or more layers stacked together, wherein at least one of the layers in the passive radiative cooling layer is a radiative cooling functional layer. Photovoltaic cell unit layer; An encapsulation layer, the encapsulation layer comprising a matrix resin and fillers doped in the matrix resin; The passive radiation cooling layer, the photovoltaic cell unit layer, and the encapsulation layer are stacked sequentially from top to bottom and connected to each other.

2. The color-tunable passively cooled photovoltaic module according to claim 1, characterized in that, The passive radiation cooling layer has an emissivity of ≥90% in the 8µm~13µm band.

3. The color-tunable passively cooled photovoltaic module according to claim 2, characterized in that, The material of the radiative cooling functional layer in the passive radiative cooling layer is selected from at least one of the following substances: TPU, PVDF and PMMA resin.

4. The color-tunable passively cooled photovoltaic module according to any one of claims 1 to 3, characterized in that, The passive radiative cooling layer further includes one or more encapsulation functional layers, which are stacked above and / or below the radiative cooling functional layers.

5. The color-tunable passively cooled photovoltaic module according to claim 4, characterized in that, The packaging functionality is layered as either EVA or POE.

6. The color-tunable passively cooled photovoltaic module according to claim 1, characterized in that, The encapsulation layer is a single-layer structure; And / or, the filler includes tinting filler and / or reflective filler.

7. The color-tunable passively cooled photovoltaic module according to claim 6, characterized in that, The color-correcting filler includes, but is not limited to, SiO2, TiO2, Al2O3 photonic crystals, and / or the reflective filler includes, but is not limited to, Y2O3, TiO2 nanosheets.

8. The color-tunable passively cooled photovoltaic module according to claim 6 or 7, characterized in that, The color-correcting filler has a mass fraction of 0.5wt% to 10wt% in the encapsulation layer, and / or the reflective filler has a mass fraction of 0.5wt% to 5wt% in the encapsulation layer.

9. The color-tunable passively cooled photovoltaic module according to claim 7, characterized in that, The D50 particle size range of the reflective filler is 50nm~800nm.

10. The color-tunable passively cooled photovoltaic module according to claim 1, characterized in that, It also includes a cover glass and a back plate, wherein the cover glass is stacked above the passive radiative cooling layer and connected to each other, and the back plate is stacked below the encapsulation layer and connected to each other.

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