Phase change temperature control photovoltaic support mechanism, preparation method thereof and BIPV system

Abstract

The application provides a phase change temperature control photovoltaic support mechanism, a preparation method thereof and a BIPV system, and belongs to the field of photovoltaic buildings. The photovoltaic support mechanism comprises a phase change base and a skeleton embedded in the phase change base. The bottom of the phase change base is flat, and the top is a wave shape with concave-convex alternation. A phase change composite material used to prepare the phase change base comprises phase change microcapsules, functional fillers, wet-mixed heat-conducting adhesive and reinforcing additives. The phase change microcapsules comprise a phase change core material and a shell layer covering the phase change core material. The functional fillers comprise flaky alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide and expanded graphite. The wet-mixed heat-conducting adhesive comprises silicone resin, alumina and disulfide bond crosslinking agents. The reinforcing additives comprise basalt short fibers. The application adopts phase change microcapsules and multiple functional additives, combines the skeleton and laminating treatment, and prepares the photovoltaic support mechanism with excellent mechanical properties, high cycle times, fire resistance, water resistance, heat absorption and temperature reduction.

Description

Technical Field

[0001] This invention belongs to the field of building photovoltaic technology, and specifically relates to a photovoltaic support structure with phase change temperature control, its preparation method, and a BIPV system. Background Technology

[0002] BIPV (Building Integrated Photovoltaic) systems refer to building-integrated photovoltaic (PV) systems that integrate solar power generation (photovoltaic) cells into buildings. BIPV systems enclose the PV cells by fixing them to the building structure (such as roofs, curtain walls, or ceilings). Currently, the mainstream fixing methods include: directly fixing the PV cells to the building structure using clips or bolts, which results in a closed contact between the back of the PV cells and the building structure, making heat dissipation difficult; or using corrugated sheets as support components, fixing them to the PV cells before connecting them to the building structure, creating a semi-closed, semi-open contact, leaving some space for external heat dissipation.

[0003] Although corrugated plates serve as a support component for BIPV systems and have a heat dissipation effect, the external environment in high-temperature weather causes a significant increase in the operating temperature of photovoltaic panels, and the corrugated plate support component does not have a good effect on improving the operating temperature of photovoltaic cells. Photovoltaic cells are greatly affected by operating temperature, specifically: (1) The increase in photovoltaic cell temperature will cause the internal resistance of the cell to increase, thereby reducing its output power and resulting in a decrease in power generation efficiency; (2) The short-circuit current of photovoltaic cells increases slightly with the increase in temperature, while the open-circuit voltage and fill factor decrease with the increase in temperature, which in turn leads to a decrease in photoelectric conversion efficiency.

[0004] To address this technical problem, existing technologies fill the corrugated plate's trough with phase change material, utilizing the principle of absorbing or releasing a large amount of latent heat during the phase change process to control and regulate temperature, thereby reducing energy consumption. However, this method suffers from drawbacks such as cumbersome processing, difficulty in fixing the phase change material, and susceptibility to leakage. Furthermore, the product also exhibits problems such as low mechanical strength, poor fire resistance and thermal conductivity, secondary pollution, short lifespan, and difficulty in replication, promotion, and mass industrial production. Summary of the Invention

[0005] Therefore, the present invention aims to provide a photovoltaic support structure with phase change temperature control, a method for its preparation, and a BIPV system, in order to solve at least one technical problem in the background art.

[0006] This invention is implemented as follows:

[0007] The first aspect of the present invention provides a photovoltaic support mechanism for phase change temperature control, the photovoltaic support mechanism comprising a phase change substrate and a frame embedded in the phase change substrate;

[0008] The bottom of the phase change matrix is ​​flat, and the top is a wave-like shape with alternating concave and convex shapes;

[0009] The surface of the skeleton is coated with a silane coupling agent.

[0010] The phase change matrix is ​​formed by curing and drying a phase change composite material; the phase change composite material includes phase change microcapsules, functional fillers, wet-mixed thermally conductive adhesives, and reinforcing additives.

[0011] The phase change microcapsule includes a phase change core material and a shell layer covering the phase change core material; the phase change core material includes a phase change material and a nucleating agent, and the phase change material is at least one of organic phase change material, inorganic phase change material, and organic-inorganic eutectic modified eutectic phase change material;

[0012] The functional fillers include flake alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide, and expanded graphite.

[0013] The wet-mixed thermally conductive adhesive includes silicone resin, alumina, and a disulfide crosslinking agent;

[0014] The reinforcing agent includes short basalt fibers.

[0015] Preferably, the weight percentages of each component in the phase change composite material are as follows:

[0016] Phase change microcapsules 50%~55%;

[0017] The functional filler comprises 25%–35%, wherein the weight percentages of flake alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide, and expanded graphite are 10%–13%, 2%–3.5%, 1%–2.5%, 7%–10%, and 4%–6%, respectively.

[0018] The wet-mixed thermally conductive adhesive comprises 10%~15%, wherein the weight percentages of silicone resin, alumina, and disulfide bond crosslinking agent are 5%~8%, 4%~5%, and 1%~2%, respectively.

[0019] Fortifying agents: 2%~5%.

[0020] Preferably, the method for preparing the phase change composite material includes:

[0021] The preheated phase change microcapsules were sprayed with a silane coupling agent-ethanol solution and then stirred to obtain pretreated phase change microcapsules.

[0022] The reinforcing agent is immersed in a silane coupling agent-ethanol solution and stirred, and then dried to obtain a pretreated reinforcing agent.

[0023] The pretreated phase change microcapsules and functional fillers are first dry-mixed, then wet-mixed thermally conductive adhesive is added and wet-mixed to form a slurry, and finally the pretreated reinforcing agent is added and stirred to form the phase change composite material.

[0024] Preferably, the organic-inorganic eutectic modified eutectic phase change material includes sodium acetate trihydrate and sorbitol, and the nucleating agent is strontium carbonate; the eutectic phase change melt prepared from sodium acetate trihydrate, sorbitol, and strontium carbonate is used as the phase change core material.

[0025] Preferably, the sodium acetate trihydrate, sorbitol, and strontium carbonate are mixed and melted at 55°C to 70°C under a nitrogen atmosphere to form the eutectic phase transformation melt;

[0026] The weight percentages of each component in the eutectic phase transformation melt are as follows:

[0027] Sodium acetate trihydrate 65%~80%;

[0028] Sorbitol 17%~25%;

[0029] Strontium carbonate 3%~10%.

[0030] Preferably, the preparation steps of the basalt short fiber are as follows: basalt fiber is cut into at least two different lengths, immersed in a dispersant solution and stirred for 10 min to 30 min, and dried at 60℃ to 80℃ to obtain the fiber; the length range is 10 mm to 60 mm.

[0031] Preferably, the skeleton is a mesh woven from wires, wherein the wires are steel wires or a mixture of steel wires and basalt fibers.

[0032] The diameter of the mesh wire is 1.0mm~1.2mm; the size of the mesh is width * length = (5mm~15mm) * (5mm~15mm).

[0033] Preferably, the outer wall of the phase change matrix is ​​provided with a coating that has waterproof and fireproof functions;

[0034] The waterproof coating is made of a two-component solvent-free epoxy primer;

[0035] The fire-retardant coating material is graphene-modified polyurethane coating or silicone resin-alumina-silane composite coating.

[0036] A second aspect of the present invention provides a method for preparing the above-mentioned phase change temperature-controlled photovoltaic support structure, which includes the following steps:

[0037] S1, lay phase change composite material in the mold to form the bottom layer of phase change matrix;

[0038] S2, lay down a layer of framework;

[0039] S3, casting, using a casting process to cover the skeleton surface with a slurry-like phase change composite material, applying vacuum pressure to make the skeleton vacuum impregnated in the phase change composite material, and forming a connecting layer of the phase change matrix after vibration compaction.

[0040] S4. If a single layer of skeleton is laid, the outer surface of the connecting layer of the phase change matrix is ​​segmented and pressed to construct a trapezoidal cross section, forming an alternating concave-convex wave shape. If multiple layers of skeleton are laid, repeat S2 and S3, and then segment the connecting layer of the last layer of the phase change matrix to construct a trapezoidal cross section, forming an alternating concave-convex wave shape.

[0041] S5, is cured and molded in sequence, dried in stages, and a coating with waterproof and fireproof properties is sprayed on the bottom and top of the phase change substrate.

[0042] Preferably, the curing conditions are: initial setting at 25℃±5℃ and 60%±5% humidity for 1h~3h, followed by heat treatment at 80℃±10℃ for 2h~3h;

[0043] The conditions for the segmented drying are: pre-drying at 50℃±5℃ for 1-2 hours, final drying at 80℃±5℃ for 2-3 hours, and finally natural cooling.

[0044] A third aspect of the present invention provides a BIPV system, which includes stacked photovoltaic cells and the aforementioned phase change temperature-controlled photovoltaic support mechanism; the back of the photovoltaic cells is in contact with the crest of the phase change substrate connecting layer, and multiple BIPV systems are spliced ​​together as one unit during installation.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. This invention uses phase change microcapsules as phase change agents, combined with functional fillers, wet-mixed thermally conductive adhesives, reinforcing additives and other functional agents, to synthesize a phase change temperature control material that is lightweight, chemically stable and high-temperature resistant. Combined with a woven skeleton, a lightweight, high-strength, high-cycle-count, long-life, fire-retardant, waterproof and heat-absorbing cooling photovoltaic support structure is obtained through lamination, thus solving the contradiction between photovoltaic cell power generation efficiency and building envelope function in the prior art.

[0047] 2. The built-in woven skeleton of this invention strengthens the mechanical properties of the material, reduces material cracking, and extends service life; it also improves thermal conductivity and phase change cycle capability; in addition, the mixed woven skeleton flat frame balances the lightweight requirements.

[0048] 3. This invention adds expanded graphite, expanded perlite, and magnesium hydroxide flame retardant to the phase change composite material, which effectively improves the thermal conductivity and stabilizes the structure, enhances the phase change cycle capability and balances the lightweight requirements, and improves the fire resistance of the material. Attached Figure Description

[0049] Figure 1 This is a three-dimensional structural diagram of the BIPV system of the present invention;

[0050] Figure 2 This is a schematic diagram of the cross-sectional structure of the photovoltaic support mechanism in Embodiment 1 of the present invention;

[0051] Figure 3 This is a schematic diagram of the cross-sectional structure of the photovoltaic support mechanism in Embodiment 2 of the present invention;

[0052] Figure 4 This is a three-dimensional structural diagram of the photovoltaic support mechanism in this invention;

[0053] Figure 5 This is a schematic diagram of the front side of the assembly structure in the photovoltaic support mechanism of the present invention;

[0054] Figure 6 This is a schematic diagram of the rear side of the assembly structure in the photovoltaic support mechanism of the present invention;

[0055] Figure 7 This is a three-dimensional schematic diagram of the female connector in this invention;

[0056] Figure 8 This is a three-dimensional schematic diagram of the rivet in this invention;

[0057] Figure 9 This is a schematic diagram of the assembly of the connecting head and the rivet in this invention.

[0058] Reference numerals: 100-Photovoltaic support structure; 110-Bottom layer; 120-Frame; 121-First layer frame; 122-Second layer frame; 130-Connecting layer; 131-First connecting layer; 132-Second connecting layer; 140-Coating; 200-Photovoltaic cell; 300-Square tube connector; 400-Connecting female head; 410-Fixing block; 420-Slot; 430-Elastic snap ring; 440-Snap ring slot; 500-Square tube slot; 600-Rivet. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0060] A method for preparing a photovoltaic support structure with phase change temperature control includes steps 1 to 3.

[0061] Step 1: Prepare phase change composite materials;

[0062] 1-1, Phase change microcapsules;

[0063] Phase change microcapsules comprise a phase change core material and a shell encapsulating the core material. The shell material can be any wall material permitted in the art, such as polymers (polyurea, PMMA), natural polymers (chitosan), titanium dioxide, polyethylene glycol, or inorganic materials (SiO2). The process of encapsulating the core material in the shell can employ any process permitted in the art, such as microfluidics, sol-gel methods, spray drying, microwave gradient curing, complex coagulation, in-situ polymerization, interfacial polymerization, etc.; no specific limitations are made here. In the following examples, urea-formaldehyde resin (76%~82%) + titanium dioxide (10%~16%) + polyethylene glycol PEG-400 (3%~8%) are used as the shell material. Phase change microcapsules are obtained by encapsulating the phase change core material in the shell.

[0064] The phase change core material includes a phase change material and a nucleating agent. The phase change material is at least one of organic phase change materials (such as paraffin), inorganic phase change materials (sodium hydrogen phosphate dodecahydrate), and organic-inorganic eutectic modified eutectic phase change materials. Preferably, the eutectic phase change material is composed of sodium acetate trihydrate and sorbitol. It can be melted with the nucleating agent strontium carbonate to form a eutectic phase change melt. Specifically, sodium acetate trihydrate (65%~80%), sorbitol (17%~25%), and strontium carbonate (3%~10%) are mixed and melted at 55℃~70℃ in a nitrogen atmosphere to form a eutectic phase change melt. The eutectic phase change melt is used as the phase change core material and encapsulated in a shell to form a phase change microcapsule.

[0065] 1-2, Raw material preparation;

[0066] Weigh the raw materials according to the following weight percentages:

[0067] Phase change microcapsules 50%~55%;

[0068] The functional filler comprises 25%–35%, wherein the weight percentages of flake alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide, and expanded graphite are 10%–13%, 2%–3.5%, 1%–2.5%, 7%–10%, and 4%–6%, respectively.

[0069] The wet-mixed thermally conductive adhesive comprises 10%~15%, wherein the weight percentages of silicone resin, alumina, and disulfide bond crosslinking agent are 5%~8%, 4%~5%, and 1%~2%, respectively.

[0070] The reinforcing agent is 2%~5%, made of basalt short fibers;

[0071] The processing method for basalt short fibers is as follows: basalt fibers are cut into at least two different lengths (between 10mm and 60mm). For example, 10mm basalt fibers and 30mm basalt fibers are mixed in a mass ratio of 3:7, immersed in a dispersant solution (KH550-ethanol mixed solution), stirred for 10 to 30 minutes, and then dried at 60℃ to 80℃ to obtain basalt short fibers. The dispersant can improve the dispersibility of basalt fibers, prevent agglomeration, and strengthen their adhesion to the slurry.

[0072] 1-3, Preparation of phase change composite materials;

[0073] The phase change microcapsules obtained in step 1-1 are first preheated, then sprayed with a silane coupling agent-ethanol solution, and then stirred to obtain pretreated phase change microcapsules.

[0074] The reinforcing agent is immersed in a silane coupling agent-ethanol solution and stirred, and then dried to obtain a pretreated reinforcing agent.

[0075] The pretreated phase change microcapsules and functional fillers are first dry-mixed, then wet-mixed thermally conductive adhesive is added and wet-mixed to form a slurry, and finally the pretreated reinforcing additives are added and stirred to form a phase change composite material.

[0076] Step 2: Prepare the skeleton;

[0077] A mesh with a width * length of (5mm~15mm) * (5mm~15mm) is formed by weaving steel wire or a mixture of steel wire and basalt fiber to create a skeleton; the mesh wire has a diameter of 1.0mm~1.2mm; a silane coupling agent is sprayed on the surface of the skeleton to enhance the interfacial bonding force between the phase change composite material and the matrix, thereby improving the compressive strength and thermal conductivity of the material.

[0078] Step 3: Prepare the photovoltaic support structure;

[0079] 3-1. Lay phase change composite material inside the mold to form the bottom layer of the phase change matrix;

[0080] 3-2, Lay a layer of skeleton, the surface of which is covered with a coating formed by silane coupling agent. In specific implementation, one or more layers of skeleton can be laid.

[0081] 3-3. Casting: The slurry-like phase change composite material is covered on the surface of the skeleton through a casting process, and then a vacuum pressure (approximately -0.08 MPa) is applied, so that the skeleton is vacuum impregnated in the phase change composite material. After vibration and compaction, a connecting layer of the phase change matrix is ​​formed. The casting process of this invention uses a casting process, which can arrange the fibers in the phase change composite material along the length direction, thereby improving the bending strength. The vacuum effect is to remove air from the skeleton, ensure complete impregnation of the slurry, and improve the interfacial bonding strength.

[0082] 3-4. If a single layer of skeleton is laid, the outer surface of the connecting layer of the phase change matrix is ​​segmented and pressed to construct a trapezoidal cross-section. If multiple layers of skeleton are laid, steps 3-2 and 3-3 are repeated, and the connecting layer of the last layer of the phase change matrix is ​​segmented and pressed to construct a trapezoidal cross-section. The trapezoidal cross-section has alternating peaks and troughs, thus forming an alternating wave shape on the outermost layer of the phase change matrix. In specific implementation, the length and width of the skeleton should be smaller than the length and width of the phase change matrix, so that the skeleton is completely enclosed in the phase change matrix.

[0083] 3-5. Curing and shaping: initial setting at 25℃±5℃ and 60%±5% humidity for 1-3 hours, followed by heat treatment at 80℃±10℃ for 2-3 hours.

[0084] 3-6. Segmented drying: Pre-dry at 50℃±5℃ for 1-2 hours, final drying at 80℃±5℃ for 2-3 hours, and finally natural cooling.

[0085] 3-7. Apply a waterproof and fireproof coating to the bottom and top of the phase change substrate. The waterproof coating is a two-component solvent-free epoxy primer with a dry film thickness of 50μm±5μm, and cure for about 2 hours until surface dry. The fireproof coating is a graphene-modified polyurethane coating or a silicone resin-alumina-silane composite coating with a dry film thickness of 150μm±10μm. Place the coating in a stepped heating tunnel: 60℃ / 20min→80℃ / 40min to form a tough film with a fire resistance rating of A1. In addition, the surface coating also has UV resistance, acid and alkali resistance, and can reduce leakage.

[0086] Two-component solvent-free epoxy primers can be purchased directly from the market or prepared at home. For example, they can be mixed in a ratio of 3~4:1 (by mass) of bisphenol F type epoxy resin (Nanya NPEF-170) and cashew phenol modified phenolic amine curing agent (Cardolite NX-2003).

[0087] The phase change material of this invention adopts a phase change microcapsule form with a phase change core and shell, which can prevent leakage of the phase change material and improve the cycle life. The phase change core material is preferably an organic-inorganic eutectic modified eutectic phase change melt, which uses sodium acetate trihydrate as a phase change agent and sorbitol as a eutectic regulator to inhibit phase separation; strontium carbonate as a nucleating agent and thermal conductivity enhancer to inhibit supercooling; and provides water of crystallization and latent heat to balance the diurnal temperature difference of 8°C to 10°C; the phase change temperature of sodium acetate trihydrate is about 58°C, and the addition of a certain amount of sorbitol can regulate the phase change temperature and avoid phase change at excessively low temperatures.

[0088] This invention uses flake-like alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide, and expanded graphite as functional fillers. Flake-like alumina and silicon carbide nanowires enhance thermal conductivity; lightweight, porous expanded perlite provides a supporting framework, reducing material density; magnesium hydroxide acts as a flame retardant, improving the material's fire resistance; its decomposition is endothermic: Mg(OH)₂ → MgO + H₂O, achieving a flame retardant efficiency of V-0 (UL94); expanded graphite improves the composite material's thermal conductivity, and its high-temperature expansion forms a carbon layer, isolating oxygen and further enhancing the overall fire resistance. The functional fillers achieve product lightweighting, reducing the density of the photovoltaic support structure to be lighter than corrugated steel sheets. The functional fillers, in synergy with the disulfide crosslinking agent, improve the cycle life of the phase change composite material and inhibit heat storage decay; based on equivalent analysis using accelerated aging tests, the service life of the phase change composite material is no less than 30 years.

[0089] This invention uses basalt short fibers as a reinforcing agent to bridge cracks, inhibit their propagation, and enhance crack resistance.

[0090] This invention uses silicone resin, alumina, and a disulfide crosslinking agent as a wet-mix thermally conductive adhesive. Impregnation ensures material density and adhesion, reducing material loosening and delamination. The silicone resin, alumina, and disulfide crosslinking agent form a composite material with a dual-network structure, where the silicone resin acts as the binder and the alumina as the thermally conductive binder. This provides a high-strength matrix and excellent thermal conductivity, along with good chemical corrosion resistance. The disulfide crosslinking agent helps repair microcracks, achieving dynamic self-healing, inhibiting the heat storage decay of the phase change agent, improving its cycle life, thickening and expanding adhesion, enhancing the material's mechanical properties, and inhibiting the supercooled phase separation of the phase change agent. Furthermore, the crosslinking network inhibits deliquescence and improves water resistance. The disulfide crosslinking agent also enables dynamic crosslinking, allowing for reversible fracture-recombination under stress, thus increasing fracture energy.

[0091] In its specific implementation, this invention preferably uses a skeleton made of a mixture of steel wire and basalt fiber. This serves three purposes: first, it improves the mechanical properties of the material, reduces cracking, and extends its service life; second, it increases thermal conductivity, enhancing phase change cycle capability; and third, the mixed-weave skeleton balances the lightweight requirements. This invention embeds a skeleton within the phase change composite material, significantly improving compressive strength; the layered pressing constructs a trapezoidal cross-section, with each layer pre-embedded with the skeleton to ensure uniform stress distribution. Testing shows that the photovoltaic support structure produced by this invention can withstand a load of at least 200 kg (≈0.2 MPa) at its center point and a dynamic load of at least 150 kg, thereby improving the safety factor and fully meeting the requirements.

[0092] The photovoltaic support structure includes a phase change substrate and a frame embedded in the phase change substrate; the bottom of the phase change substrate is flat, and the top is an alternating wavy shape. The phase change substrate includes a bottom layer and a connecting layer; the bottom of the bottom layer is flat, and the top of the connecting layer is an alternating wavy shape. Both the bottom of the bottom layer and the top of the connecting layer are coated with a waterproof and fireproof coating. If only one frame is laid, there is only one connecting layer; if multiple frames are laid, the number of connecting layers is the same as the number of frame layers, and the alternating wavy shape and sprayed coating are only formed on the outermost connecting layer.

[0093] In implementation, several photovoltaic cells are fixedly mounted on a photovoltaic support structure using adhesive materials. The photovoltaic cells can be double-glass or single-glass. Specifically, the back panel of the photovoltaic cell is connected to the crest of the phase change substrate bonding layer to form a BIPV system. During installation, multiple BIPV systems are spliced ​​together as a single unit, and its assembly structure is as follows: Figure 1 As shown.

[0094] Example 1

[0095] The fabrication method of the phase change temperature-controlled photovoltaic support structure includes steps 1 to 3, to obtain the structure as shown in the figure. Figure 2 The photovoltaic support structure shown.

[0096] Step 1: Weigh the raw materials according to sodium acetate trihydrate (75%), sorbitol (20%), and strontium carbonate (5%), heat them to 65°C under a nitrogen atmosphere, stir and melt them for about 2 hours to form a eutectic phase change melt, which serves as the phase change core material; weigh the raw materials according to urea-formaldehyde resin (80%), titanium dioxide (15%), and polyethylene glycol (5%), stir them evenly to obtain a shell precursor; take the eutectic phase change melt and shell precursor at a mass ratio of 5:1, mix them, shear and homogenize them, and then obtain phase change microcapsules by spray drying.

[0097] A silane coupling agent-ethanol solution was prepared by diluting KH-550 silane coupling agent with ethanol at a mass ratio of 100:1. 51.5 parts of phase change microcapsules were preheated to 60°C and sprayed onto their surface using the silane coupling agent-ethanol solution, stirred at 300 rpm for 20 minutes. Then, 12 parts of flake alumina, 3 parts of silicon carbide nanowires, 2 parts of expanded perlite, 10 parts of magnesium hydroxide, and 6 parts of expanded graphite were added and mechanically stirred until homogeneous for dry mixing. Finally, 8 parts of silicone resin, 4.5 parts of alumina, and 1 part of double... A sulfur bond crosslinking agent was used to wet-mix and crosslink the material under a vacuum of -0.1 MPa at 1000 rpm for 15 minutes, with the viscosity controlled within the range of 8000 cP to 12000 cP, to form a uniform thermally conductive adhesive slurry. Two parts of basalt short fibers were immersed in a silane coupling agent-ethanol solution and stirred for about 20 minutes. After drying at 70°C, the fibers were added to the slurry and stirred using a "scraping-stirring" method (30 rpm for 5 minutes) to ensure that the fibers were evenly dispersed without breaking. After stirring at low speed, a slurry-like phase change composite material was obtained.

[0098] Step 2: Take steel wire with a diameter of about 1.0 mm and weave it into a mesh with a width * length = 10 mm * 10 mm to make a skeleton; then spray silane coupling agent on the surface of the skeleton.

[0099] Step 3: Lay the phase change composite material (approximately 30mm thick) obtained in Step 1 into the mold to form the bottom layer of the phase change matrix; lay a layer of the skeleton obtained in Step 2; cast the mixture by using a casting process to cover the skeleton surface with the slurry-like phase change composite material (approximately 30mm thick), then apply vacuum pressure (approximately -0.08MPa) to vacuum impregnate the skeleton in the phase change composite material. After vibration compaction (50Hz, 30s), a connecting layer of the phase change matrix is ​​formed; the outer surface of the connecting layer of the phase change matrix is ​​segmented and pressed to construct a trapezoidal cross-section, with a peak of approximately 60mm and a trough of approximately 20mm, thus forming an interlocking convex-concave cross-section. The substrate is formed by alternating wavy layers, with the bottom layer and connecting layer constituting the phase change matrix. It undergoes initial setting at 25℃±5℃ and 60%±5% humidity for 2 hours, followed by heat treatment at 80℃±10℃ for 2 hours to solidify the matrix. It is then pre-dried at 50℃±5℃ for 1.5 hours, finally dried at 80℃±5℃ for 3 hours, and then allowed to cool naturally. A two-component solvent-free epoxy primer with a dry film thickness of approximately 50μm is sprayed onto the bottom of the bottom layer and the top of the connecting layer to provide waterproofing. A graphene-modified polyurethane coating with a dry film thickness of approximately 150μm is then sprayed on to provide fire resistance. After drying, a coating with both waterproof and fire-resistant properties is formed, thus creating the photovoltaic support structure.

[0100] like Figure 2As shown, the photovoltaic support structure 100 includes a phase change substrate and a frame 120 embedded in the phase change substrate; the bottom of the phase change substrate is flat, and the top is a wave-like shape with alternating concave and convex shapes. The phase change substrate includes a bottom layer 110 and a connecting layer 130, the bottom of the bottom layer 110 is flat, and the top of the connecting layer 130 is a wave-like shape with alternating concave and convex shapes. Both the bottom of the bottom layer 110 and the top of the connecting layer 130 are provided with a coating 140 that has waterproof and fireproof functions.

[0101] In this embodiment, photovoltaic cells 200 are installed on the photovoltaic support structure 100 to assemble a BIPV system, such as... Figure 1 As shown, the BIPV system includes a stacked photovoltaic support structure 100 and photovoltaic cells 200. In a specific implementation, several photovoltaic cells 200 are fixedly installed on the photovoltaic support structure 100 using adhesive materials. The photovoltaic cells can be double-glass or single-glass photovoltaic cells. The photovoltaic support structure is also equipped with a splicing and fastening structure for quickly assembling two BIPV systems into one unit.

[0102] See Figures 4 to 6 In the photovoltaic support structure 100, the front side of the bottom layer 110 is concave relative to the connecting layer 130, and the rear side of the bottom layer 110 is convex relative to the connecting layer 130. That is, the bottom layer 110 of the phase change substrate and the connecting layer 130 form a misaligned structure, and the concave and convex parts fit together during assembly. The splicing and fastening structure includes a square tube connector 300 installed on the outer edge region of the phase change substrate, a square tube slot 500 that matches the square tube connector 300, a connecting female head 400, and a rivet 600.

[0103] In this design, rivet 600 is installed on the rear outward protrusion of the bottom layer 110, and connecting head 400 is installed in the corresponding trough area of ​​the connecting layer 130 on the front side of the bottom layer 110. The rivet 600 and connecting head 400 form a riveting assembly. For example... Figures 7 to 9 As shown, the connecting female head 400 includes a fixing block 410 with a slot 420, which matches the rivet 600. The fixing block 410 has a retaining spring groove 440 inside, and an elastic retaining spring 430 is movably installed in the retaining spring groove 440. The elastic retaining spring 430 is partially exposed on the outside of the slot 420. When assembling the two sets of BIPV systems, the rivet 600 is pushed into the slot 420 of the connecting female head 400. When the rivet 600 is pushed, it contacts the elastic retaining spring 430 and forms an inward pushing force on its exposed part, causing the elastic retaining spring 430 to retract into the retaining spring groove 440. When the rivet 600 is fully embedded in the slot 420, it disengages from the elastic retaining spring 430, and the elastic retaining spring 430 returns to its initial shape, so that the rivet 600 is fixed in the slot 420 and prevents it from sliding off.

[0104] like Figures 4 to 6As shown, the square tube connector 300 and the square tube slot 500 are both installed in the peak area of ​​the connecting layer 130 and extend downward to the bottom layer 110. The square tube connector 300 is provided at one end and the square tube slot 500 is provided at the other end. The square tube connector 300 and the square tube slot 500 are staggered on the same side in the horizontal direction.

[0105] After the two sets of photovoltaic support mechanisms 100 are spliced ​​together, the rivet 600 is connected to the connecting female head 400 and the square tube joint 300 is connected to the square tube slot 500, so as to achieve rapid assembly and form a stable and easy-to-disassemble BIPV system.

[0106] Example 2

[0107] The only difference between this embodiment and Embodiment 1 is that two layers of skeleton are set in step 3; the other steps and conditions are the same as in Embodiment 1, resulting in the following: Figure 3 The photovoltaic support structure shown.

[0108] Step 3 in this embodiment is specifically as follows:

[0109] The phase change composite material (approximately 15 mm thick) prepared in step 1 is laid in the mold to form the bottom layer 110 of the phase change matrix; the first skeleton layer 121 is laid; casting is performed by covering the skeleton surface with a slurry-like phase change composite material (approximately 15 mm thick) using a casting process, and then a vacuum pressure (approximately -0.08 MPa) is applied to vacuum impregnate the skeleton in the phase change composite material. After vibration compaction, the first connecting layer 131 of the phase change matrix is ​​formed; the second skeleton layer 122 is laid; a second casting is performed by covering the skeleton surface with a slurry-like phase change composite material using a casting process, and then a vacuum pressure (approximately -0.08 MPa) is applied to vacuum impregnate the skeleton in the phase change composite material (approximately 30 mm thick). After vibration compaction, the second connecting layer 132 of the phase change matrix is ​​formed; the outer surface of the second connecting layer 132 of the phase change matrix is ​​divided. The trapezoidal cross-section is constructed by segmental pressing, with peaks of approximately 60 mm and troughs of approximately 20 mm, forming an alternating wave shape. The bottom layer 110, the first connecting layer 131, and the second connecting layer 132 constitute the phase change matrix. The matrix is ​​initially set at 25℃±5℃ and 60%±5% humidity for 2 hours, followed by heat treatment at 80℃±10℃ for 2 hours to solidify it. It is then pre-dried at 50℃±5℃ for 1.5 hours, finally dried at 80℃±5℃ for 3 hours, and then allowed to cool naturally. A two-component solvent-free epoxy primer with a dry film thickness of approximately 50 μm is sprayed onto the bottom of the bottom layer 110 and the top of the second connecting layer 132 to provide waterproofing. A graphene-modified polyurethane coating with a dry film thickness of approximately 150 μm is then sprayed on to provide fire resistance. After drying, a coating 140 with both waterproof and fire-resistant properties is formed, thus creating the photovoltaic support structure.

[0110] like Figure 3As shown, the photovoltaic support structure 100 includes a phase change substrate and a frame embedded in the phase change substrate; the bottom of the phase change substrate is flat, and the top is a wave-like shape with alternating concave and convex shapes. The phase change substrate includes a bottom layer 110, a first connecting layer 131, and a second connecting layer 132. A first frame 121 is built between the bottom layer 110 and the first connecting layer 131, and a second frame 122 is built between the first connecting layer 131 and the second connecting layer 132. The bottom of the bottom layer 110 is flat, and the top of the second connecting layer 132 is a wave-like shape with alternating concave and convex shapes. Both the bottom of the bottom layer 110 and the top of the second connecting layer 132 are provided with a coating 140 that has waterproof and fireproof functions.

[0111] Example 3

[0112] The only difference between this embodiment and Embodiment 1 is that in step 2, the mesh of the woven skeleton is adjusted to be a mixture of steel wire and basalt fiber, that is, steel wire is used in the longitudinal direction and basalt fiber is used in the transverse direction. The other steps and conditions are the same as in Embodiment 1.

[0113] Example 4

[0114] The only difference between this embodiment and Embodiment 1 is that the material of the fire-retardant coating in step 3 is changed to a silicone resin-alumina-silane composite coating. The other steps and conditions are the same as in Embodiment 1.

[0115] Example 5

[0116] The only difference between this embodiment and Example 1 is that the weight of each component of the phase change composite material in step 1 is adjusted to: 50 parts phase change microcapsules, 10 parts flake alumina, 3 parts silicon carbide nanowires, 2 parts expanded perlite, 8 parts magnesium hydroxide, 5 parts expanded graphite, 8 parts silicone resin, 5 parts alumina, 2 parts disulfide crosslinking agent and 5 parts basalt short fibers. The other steps and conditions are the same as in Example 1.

[0117] Example 6

[0118] The only difference between this embodiment and Example 1 is that the weight of each component of the phase change composite material in step 1 is adjusted to: 55 parts phase change microcapsules, 13 parts flake alumina, 2 parts silicon carbide nanowires, 1 part expanded perlite, 8 parts magnesium hydroxide, 4 parts expanded graphite, 7 parts silicone resin, 4 parts alumina, 2 parts disulfide crosslinking agent and 4 parts basalt short fibers. The other steps and conditions are the same as in Example 1.

[0119] Example 7

[0120] The only difference between this embodiment and Embodiment 1 is that the weight percentages of each component in the eutectic phase change melt in step 1 are adjusted to: sodium acetate trihydrate 65%, sorbitol 30%, and strontium carbonate 5%. The other steps and conditions are the same as in Embodiment 1.

[0121] In step 1 of this embodiment, the specific steps for preparing phase change microcapsules are as follows: raw materials are weighed according to sodium acetate trihydrate (65%), sorbitol (30%), and strontium carbonate (5%), and heated to 65°C under a nitrogen atmosphere and stirred and melted for about 2 hours to form a eutectic phase change melt; raw materials are weighed according to urea-formaldehyde resin (80%), titanium dioxide (15%), and polyethylene glycol PEG-400 (5%), and stirred evenly to obtain a shell precursor; the eutectic phase change melt and shell precursor are taken according to a mass ratio of eutectic phase change melt: shell precursor = 5:1, mixed and sheared to homogenize, and then obtained by spray drying to obtain phase change microcapsules.

[0122] Example 8

[0123] The only difference between this embodiment and Embodiment 1 is that the weight percentages of each component in the eutectic phase change melt in step 1 are adjusted to: sodium acetate trihydrate 70%, sorbitol 20%, and strontium carbonate 10%. The other steps and conditions are the same as in Embodiment 1.

[0124] In step 1 of this embodiment, the specific steps for preparing phase change microcapsules are as follows: raw materials are weighed according to sodium acetate trihydrate (70%), sorbitol (20%), and strontium carbonate (10%), and heated to 65°C under a nitrogen atmosphere and stirred and melted for about 2 hours to form a eutectic phase change melt; raw materials are weighed according to urea-formaldehyde resin (80%), titanium dioxide (15%), and polyethylene glycol (5%), and stirred evenly to obtain a shell precursor; the eutectic phase change melt and shell precursor are taken according to a mass ratio of eutectic phase change melt: shell precursor = 5:1, mixed and sheared to homogenize, and then obtained by spray drying to obtain phase change microcapsules.

[0125] The performance of the photovoltaic support structures in Examples 1 to 8 was tested using the following specific testing methods or standards:

[0126] (1) Compressive strength: The compressive strength was tested in accordance with ASTM D695 "Compression properties of rigid plastics";

[0127] (2) Crack resistance: The fracture energy was tested in accordance with GB / T 50082—2024 "Standard for Test Methods of Long-term Performance and Durability of Concrete";

[0128] (3) Fire resistance performance: The fire resistance rating shall be tested in accordance with GB 8624-2012 "Classification of Combustion Performance of Building Materials and Products";

[0129] (4) Flame retardant performance: The flame retardant rating shall be tested in accordance with GB / T 9978.2-2019 "Fire Resistance Test of Building Components";

[0130] (5) Waterproof performance: The water absorption rate was tested in accordance with GB 55030-2022 "General Specification for Waterproofing of Building and Municipal Engineering";

[0131] (6) Thermal conductivity: The thermal conductivity was tested in accordance with ASTM E1461, "Test method for determining the thermal diffusivity of solids by the flash method (laser flash method)".

[0132] (7) Density: Detects mass and volume; the mass per unit volume is the density.

[0133] (8) Heat storage and heat storage decay: DSC (differential scanning calorimetry) was used in combination with physical heat storage to test.

[0134] The performance test results are shown in Table 1.

[0135] Table 1

[0136]

[0137] As can be seen from the data in Table 1, the photovoltaic support structure prepared in Examples 1 to 8 of the present invention has the effects of being lightweight, high-strength, having a high cycle life, long life, fireproof, waterproof, and heat absorption and cooling.

[0138] Comparative Example 1

[0139] The only difference between this comparative example and Example 1 is the deletion of any one of the following components in step 1: flake alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide, expanded graphite, disulfide crosslinking agent, or basalt short fibers; or the deletion of the skeleton in step 2. All other steps and conditions are the same as in Example 1. The study lacks an understanding of the impact of a single component on the performance of the photovoltaic support structure. Specific testing methods or standards are the same as in Example 1, and the results are shown in Table 2.

[0140] Table 2

[0141]

[0142] As shown in Table 2, removing any one of the following components—flaky alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide and expanded graphite, disulfide crosslinking agent, basalt short fibers, or the framework—significantly reduces the performance of the resulting photovoltaic support structure. Specifically, this includes:

[0143] When there is a lack of flake-like alumina, a three-dimensional heat conduction network cannot be constructed, the horizontal heat conduction path is destroyed, and the thermal conductivity drops significantly.

[0144] Without silicon carbide nanowires, it is impossible to construct a three-dimensional thermally conductive network, the thermal bridging in the vertical direction fails, and the thermal conductivity will also decrease significantly.

[0145] When expanded perlite is lacking, the compressive strength is slightly increased due to the relative increase in the matrix content, but some toughness is sacrificed and the product density and weight are increased.

[0146] Without magnesium hydroxide, a heat-absorbing flame-retardant synergistic flame-retardant system cannot be formed, and the fire rating is reduced from A1 to B1.

[0147] Without expanded graphite, an expanded oxygen-barrier synergistic flame-retardant system cannot be formed, and the fire rating is reduced from A1 to B1.

[0148] In the absence of disulfide crosslinking agents, the self-healing ability is lost, interfacial cracks propagate, fracture energy decreases, and the decay rate after cycling increases significantly.

[0149] When basalt short fibers are lacking, the compressive strength decreases and the decay rate after cycling increases significantly.

[0150] Without the framework, the material loses its primary load-bearing structure, resulting in a drastic drop in compressive strength of approximately 49%, rendering it a purely functional material. The framework is the main load-bearing structure; its removal causes a sharp decline in both compressive strength and toughness.

[0151] Comparative Example 2

[0152] The only difference between this comparative example and Example 1 is that sodium acetate trihydrate, sorbitol, or strontium carbonate were removed from the phase change core material of the phase change microcapsules in step 1. All other steps and conditions were the same as in Example 1. The study investigated the effect of a single component in the phase change core material on the performance of the photovoltaic support structure. Specific testing methods or standards were the same as in Example 1, and the results are shown in Table 3.

[0153] Table 3

[0154]

[0155] As shown in Table 3, removing any one of the components—sodium acetate trihydrate, sorbitol, or strontium carbonate—from the phase change core material significantly reduces the performance of the resulting photovoltaic support structure. Specifically, this includes:

[0156] Without sodium acetate trihydrate, the product loses its function completely, and the thermal conductivity collapses due to the removal of the main heat conduction path (PCM core). The performance related to phase change energy storage (enthalpy, heat storage) drops directly to zero.

[0157] The absence of sorbitol severely disrupts system coordination. After multiple melt-crystallization cycles, sodium acetate trihydrate will irreversibly separate into a salt-rich phase and a water-rich phase, resulting in a significant 20% decrease in heat storage, a sharp drop in cycle life, and a soaring decay rate.

[0158] In the absence of strontium carbonate, functional specificity collapses, the nucleation barrier is significantly reduced and the supercooling is increased, phase transition cycling cannot crystallize normally, performance immediately degrades, and directly leads to the end of cycle life.

[0159] Comparative Example 3

[0160] The only difference between this comparative example and Example 1 is that the phase change microcapsule morphology is not used in step 1 when preparing the phase change composite material, i.e., the phase change core material is not encapsulated; the other steps and conditions are the same as in Example 1. The specific testing methods or standards for the performance of the obtained photovoltaic support structure are the same as in Example 1, and the results are shown in Table 4.

[0161] Step 1 of this comparative example is as follows: Raw materials are weighed according to sodium acetate trihydrate (75%), sorbitol (20%), and strontium carbonate (5%). The mixture is heated to 65°C under a nitrogen atmosphere and stirred and melted for approximately 2 hours to form a eutectic phase change melt. A silane coupling agent-ethanol solution is prepared by diluting KH-550 silane coupling agent with ethanol at a mass ratio of 100:1. 51.5 parts of the eutectic phase change melt are weighed and preheated to 60°C. The surface of the melt is sprayed with the silane coupling agent-ethanol solution and stirred at 300 rpm for 20 minutes. Then, 12 parts of flake-shaped alumina, 3 parts of silicon carbide nanowires, 2 parts of expanded perlite, and 10 parts of magnesium hydroxide are added. The expanded graphite was mechanically stirred to form a dry mixture. Then, 8 parts of silicone resin, 4.5 parts of alumina, and 1 part of disulfide crosslinking agent were added. The mixture was stirred at 1000 rpm for 15 minutes under a vacuum of -0.1 MPa, with the viscosity controlled within the range of 8000 cP-12000 cP, to form a uniform thermally conductive adhesive slurry. Two parts of basalt short fibers were immersed in a silane coupling agent-ethanol solution and stirred for about 20 minutes. After drying at 70°C, the fibers were added to the slurry. The mixture was stirred at a "scraping-stirring" mode (30 rpm, 5 minutes) to ensure that the fibers were evenly dispersed without breaking. After stirring at low speed, a slurry-like phase change composite material was obtained.

[0162] Comparative Example 4

[0163] The only difference between this comparative example and Example 1 is that: in step 2, no silane coupling agent is sprayed on the skeleton surface; the other steps and conditions are the same as in Example 1.

[0164] Comparative Example 5

[0165] The only difference between this embodiment and Embodiment 1 is that the wet-mixed thermally conductive adhesive in step 1 is adjusted to a common adhesive that does not have thermal conductivity, namely silicone resin. The other steps and conditions are the same as in Embodiment 1.

[0166] The specific testing methods or standards for the photovoltaic support structures prepared in Comparative Examples 3 to 5 are the same as those in Example 1, and the comparison results with Example 1 are shown in Table 4.

[0167] Table 4

[0168]

[0169] As shown in Table 4, changing the preparation process significantly alters the product performance, as detailed below:

[0170] In Comparative Example 3, the phase change core material was not encapsulated in microcapsules, which caused easy leakage of crystal water, resulting in a drop of more than 50% in the decay rate and cycle count, and a reduction of more than 50% in the product's phase change temperature control life.

[0171] In Comparative Example 4, the skeleton surface was not coated with silane coupling agent, resulting in a decrease in fracture resistance of more than 10%, and the product's attenuation rate was more than double that of Example 1.

[0172] When the wet-mixed thermally conductive adhesive in Comparative Example 5 was adjusted to a regular adhesive that does not have thermal conductivity, the thermal conductivity decreased by more than 60%, the fracture resistance decreased by nearly 30%, and the fireproof and flame-retardant properties decreased.

[0173] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A photovoltaic support mechanism with phase change temperature control, characterized in that, The photovoltaic support structure includes a phase change substrate and a frame embedded in the phase change substrate; the photovoltaic cells are fixedly installed on the photovoltaic support structure by adhesive materials to form a BIPV system; The bottom of the phase change matrix is ​​flat, and the top is a wave-like shape with alternating concave and convex shapes; The skeleton surface is coated with a silane coupling agent; the skeleton is a mesh woven from wires, the wires being steel wires or a mixture of steel wires and basalt fibers, the diameter of the wires being 1.0mm~1.2mm; the size of the mesh is width * length = (5mm~15mm) * (5mm~15mm). The phase change matrix is ​​formed by curing and drying a phase change composite material; the phase change composite material includes phase change microcapsules, functional fillers, wet-mixed thermally conductive adhesives and reinforcing additives; the slurry-like phase change composite material is covered on the surface of the skeleton by a casting process, and vacuum pressure is applied so that the skeleton is vacuum impregnated in the phase change composite material; The phase change microcapsule includes a phase change core material and a shell layer covering the phase change core material; the phase change core material includes a phase change material and a nucleating agent, and the phase change material is at least one of organic phase change material, inorganic phase change material, and organic-inorganic eutectic modified eutectic phase change material; The functional fillers include flake alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide, and expanded graphite. The wet-mixed thermally conductive adhesive includes silicone resin, alumina, and a disulfide crosslinking agent; The reinforcing agent includes basalt short fibers; the processing method of basalt short fibers is as follows: basalt fibers are cut into at least two different lengths, mixed, immersed in a dispersant solution and stirred for 10 to 30 minutes, and then dried at 60°C to 80°C to obtain basalt short fibers.

2. The photovoltaic support mechanism with phase change temperature control according to claim 1, characterized in that, The weight percentages of each component in the phase change composite material are as follows: Phase change microcapsules 50%~55%; The functional filler comprises 25%–35%, wherein the weight percentages of flake alumina, silicon carbide nanowires, expanded perlite, magnesium hydroxide, and expanded graphite are 10%–13%, 2%–3.5%, 1%–2.5%, 7%–10%, and 4%–6%, respectively. The wet-mixed thermally conductive adhesive comprises 10%~15%, wherein the weight percentages of silicone resin, alumina, and disulfide bond crosslinking agent are 5%~8%, 4%~5%, and 1%~2%, respectively. Fortifying agents: 2%~5%.

3. The photovoltaic support mechanism with phase change temperature control according to claim 2, characterized in that, The preparation method of the phase change composite material includes: The preheated phase change microcapsules were sprayed with a silane coupling agent-ethanol solution and then stirred to obtain pretreated phase change microcapsules. The reinforcing agent is immersed in a silane coupling agent-ethanol solution and stirred, and then dried to obtain a pretreated reinforcing agent. The pretreated phase change microcapsules and functional fillers are first dry-mixed, then wet-mixed thermally conductive adhesive is added and wet-mixed to form a slurry, and finally the pretreated reinforcing agent is added and stirred to form the phase change composite material.

4. The photovoltaic support mechanism with phase change temperature control according to claim 2, characterized in that, The organic-inorganic eutectic modified eutectic phase change material includes sodium acetate trihydrate and sorbitol, and the nucleating agent is strontium carbonate; a eutectic phase change melt is prepared from sodium acetate trihydrate, sorbitol, and strontium carbonate as the phase change core material.

5. The photovoltaic support mechanism with phase change temperature control according to claim 4, characterized in that, The sodium acetate trihydrate, sorbitol, and strontium carbonate are mixed and melted under a nitrogen atmosphere at 55°C to 70°C to form the eutectic phase transformation melt. The weight percentages of each component in the eutectic phase transformation melt are as follows: Sodium acetate trihydrate 65%~80%; Sorbitol 17%~25%; Strontium carbonate 3%~10%.

6. The photovoltaic support mechanism with phase change temperature control according to claim 2, characterized in that, The preparation steps of the basalt short fiber are as follows: cut the basalt fiber into at least two different lengths, immerse it in a dispersant solution and stir for 10 min to 30 min, and dry it at 60℃ to 80℃ to obtain the fiber; the length range is 10 mm to 60 mm.

7. The photovoltaic support mechanism with phase change temperature control according to claim 1, characterized in that, The outer wall of the phase change matrix is ​​provided with a coating that has waterproof and fireproof functions; The waterproof coating is made of a two-component solvent-free epoxy primer; The fire-retardant coating material is graphene-modified polyurethane coating or silicone resin-alumina-silane composite coating.

8. The method for preparing the phase change temperature-controlled photovoltaic support structure according to any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: S1, lay phase change composite material in the mold to form the bottom layer of phase change matrix; S2, lay down a layer of framework; S3, casting, using a casting process to cover the skeleton surface with a slurry-like phase change composite material, applying vacuum pressure to make the skeleton vacuum impregnated in the phase change composite material, and forming a connecting layer of the phase change matrix after vibration compaction. S4. If a single layer of skeleton is laid, the outer surface of the connecting layer of the phase change matrix is ​​segmented and pressed to construct a trapezoidal cross section, forming an alternating concave-convex wave shape. If multiple layers of skeleton are laid, repeat S2 and S3, and then segment the connecting layer of the last layer of the phase change matrix to construct a trapezoidal cross section, forming an alternating concave-convex wave shape. S5 is then cured and dried in stages, and a waterproof and fireproof coating is sprayed on the bottom and top of the phase change substrate.

9. A BIPV system, characterized in that, The BIPV system includes stacked photovoltaic cells and a photovoltaic support structure for phase change temperature control as described in any one of claims 1 to 7; the back of the photovoltaic cells is in contact with the crest of the phase change substrate connection layer, and multiple BIPV systems are spliced ​​together as one unit during installation.

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