A passive radiative cooling energy storage device with photovoltaic synergistic function applied to a vanadium redox flow battery system

Abstract

This invention belongs to the field of electrochemical energy storage and photovoltaic thermal management technology, specifically relating to a passive radiative cooling energy storage device with photovoltaic enhancement function applied to a vanadium redox flow battery system. By cleverly combining a cooling coating and bifacial photovoltaic technology, this invention successfully solves the key temperature control and energy efficiency challenges of outdoor operation of vanadium redox flow batteries. Zero energy consumption achieves efficient equipment cooling; experimental tests show that the surface temperature of the container is reduced by >22°C, and the internal temperature by >14°C; it significantly reduces active cooling energy consumption, with air conditioning energy consumption reduced by >46%; it effectively increases photovoltaic power generation, with an average daily power generation increase of >7%; it promotes complementary and synergistic operation of photovoltaic and energy storage, improving system energy efficiency and economy; and it boasts high space utilization and simple installation and maintenance. This invention provides an innovative and efficient solution for improving the operating efficiency, reliability, economy, and sustainability of vanadium redox flow battery energy storage systems in high-temperature environments.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage and photovoltaic thermal management technology, specifically relating to a passive radiative cooling energy storage device with photovoltaic efficiency enhancement function applied to a vanadium redox flow battery system. Background Technology

[0002] Vanadium redox flow batteries are currently the mainstream technology for large-scale, long-term energy storage, generally employing a containerized integrated structure with the electrolyte stored in external tanks. Due to prolonged exposure to outdoor sunlight, the surfaces of the containers and tanks absorb significant amounts of solar radiation heat, leading to increased internal temperatures and electrolyte temperatures. This accelerates side reactions in the electrolyte, increases membrane resistance, and reduces battery efficiency and lifespan. Currently, these systems primarily rely on active cooling methods such as air conditioning and fans for temperature control, resulting in high energy consumption, high operating costs, and a significant reduction in overall system energy efficiency.

[0003] Passive radiative cooling can achieve cooling by highly reflective sunlight and dissipating heat into outer space in the form of infrared radiation under zero-energy conditions, making it an ideal solution to the high-temperature problem of energy storage systems. However, traditional white coatings have low reflectivity and emissivity, resulting in limited cooling effects and making it difficult to meet the long-term stable operation requirements of energy storage systems. Furthermore, the top space of the container is not effectively utilized, and the photovoltaic and energy storage systems operate independently, failing to achieve synergistic effects.

[0004] Therefore, this invention addresses the problems of existing vanadium redox flow battery containers and electrolyte storage tanks, which suffer from severe heat absorption during outdoor operation, reliance on high-energy-consuming active cooling, and low utilization efficiency of the container's top space. The key technical problem this invention aims to solve is how to design a photovoltaic-storage complementary system that achieves zero-energy passive cooling of the main equipment while simultaneously utilizing reflected light to improve photovoltaic power generation efficiency. The photovoltaic power generated can then be used to support system operation or prioritize power supply to the load. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a passive radiative cooling energy storage device with photovoltaic enhancement function applied to a vanadium redox flow battery system. A high-performance ADS / PDMS passive radiative cooling coating is integrated with a bifacial photovoltaic double-glass module and applied to the vanadium redox flow battery system, focusing on enhancing the spectral selectivity and cooling capacity of the radiative cooling material. Simultaneously, reflected light is used to increase photovoltaic power generation, fundamentally solving problems such as severe heat absorption, high active cooling energy consumption, and insufficient photovoltaic-storage synergy in outdoor energy storage systems.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides an integrated vanadium redox flow battery energy storage system combining photovoltaic (PV) enhancement and passive radiative cooling. The system includes a vanadium redox flow battery container, positive and negative electrolyte tanks, an ADS / PDMS passive radiative cooling coating, a double-glass photovoltaic module, a support structure, and ventilation gaps. The cooling coating is applied to the top of the container, the south / west-facing sidewalls, and the outer surface of the electrolyte tanks. The double-glass photovoltaic module is mounted on the top of the container via a support structure, maintaining ventilation gaps between it and the top surface of the container. The ADS / PDMS cooling coating uses PDMS as a substrate and is doped with aggregated dense silica (ADS) particles, exhibiting a solar reflectance (SR) ≥ 80%, an 8-13μm infrared emissivity (ε) ≥ 91%, and a visible light transmittance ≥ 70%. The double-glass photovoltaic module is a bifacial power generation module, receiving direct sunlight on the front and reflected light from the cooling coating on the back, forming a photovoltaic-storage complementary system.

[0007] Furthermore, the preparation method of the ADS / PDMS passive radiation cooling coating includes the following steps: Step S1, Preparation of ADS particles: Using nano-silica particles as raw materials and deionized water as the dispersion medium, prepare a nano-silica dispersion; disperse the prepared dispersion by ultrasonication and high-speed stirring to ensure that the nano-silica particles are completely dispersed and do not agglomerate; spray dry the dispersed liquid to ensure that the liquid droplets are in full contact with hot air, the water in the droplets evaporates instantly, and the nano-silica particles self-assemble and aggregate to form ADS particles; collect the dried product to obtain ADS particles. Step S2, Preparation of ADS / PDMS passive radiation cooling coating: Mix PDMS base adhesive and PDMS curing agent, stir and let stand to degas, to obtain PDMS mixed base adhesive; add ADS particles to PDMS mixed base adhesive, stir manually to disperse, so that ADS particles are evenly dispersed in base adhesive, to obtain ADS / PDMS mixed slurry; pour ADS / PDMS mixed slurry onto a clean and flat substrate, and form a film preform by scraping; heat to cure, cool and peel off the film preform to obtain ADS / PDMS passive radiation cooling coating.

[0008] Furthermore, in step S1, the nano-silica particles are monodisperse dense silica (SDS) with a purity ≥99.9% and a particle size of 117±5nm.

[0009] Furthermore, in step S1, the mass fraction of the nano-silica dispersion is 1-5%.

[0010] Furthermore, in step S1, during the spray drying process, the hot air outlet temperature is controlled at 60±5℃ to avoid high-temperature sintering of ADS particles.

[0011] Further, in step S2, the mass fraction of the ADS particles in the PDMS mixed base adhesive is 3-7%.

[0012] Further, in step S2, the substrate is a glass substrate or a PET flexible substrate, which is ultrasonically cleaned with ethanol, rinsed with deionized water, and dried before use.

[0013] Furthermore, the thickness of the film preform is 600±50μm.

[0014] The radiation cooling mechanism of the ADS / PDMS passive radiation cooling coating is as follows: monodisperse nano-silica is spray-dried to prepare aggregated dense silica (ADS), forming a nano-micro multi-level agglomeration structure; in the visible light band, backscattering is converted into forward scattering through near-field coupling and multiple scattering, ensuring high transmittance; in the near-infrared band, thermal reflection is significantly improved by micron-scale Mie scattering and multiple scattering; and the high infrared emissivity of the PDMS matrix is ​​maintained in the 8-13 μm atmospheric window, thereby achieving synergistic optimization of high visible light transmittance, high near-infrared reflectance, and high infrared emissivity, significantly improving the passive daytime radiation cooling performance.

[0015] Furthermore, the ventilation gap height is 0.2-0.5m to achieve natural convection heat dissipation and further reduce the temperature of the enclosure and photovoltaic backsheet.

[0016] Furthermore, the photovoltaic double-glass modules are installed at the local latitude tilt angle, which increases the power generation by ≥7.5% compared to single-sided modules. The generated power is prioritized for supplying system pumps, control units, and air conditioning, reducing dependence on the power grid.

[0017] Furthermore, the photovoltaic double-glass module is connected to the vanadium redox flow battery system via an inverter, and the generated power is used to support system operation (such as auxiliary pumps and control power) or to prioritize power supply to the load, thus forming a photovoltaic-storage complementary system.

[0018] Compared with the prior art, the beneficial effects of the present invention are: (1) The ADS / PDMS passive radiation cooling coating of the present invention has a multi-level scattering structure of aggregated dense silica (ADS), which takes into account both high visible light transmittance (≥70%) and high near-infrared reflectivity (≥80%), combined with the high infrared emission characteristics of PDMS (≥91.2%), which can effectively block solar heat energy and radiate heat to space, significantly alleviating the problem of high temperature efficiency degradation of photovoltaic modules; the preparation method is simple and does not require complex equipment. The core steps are dispersion, spray drying, mixing and coating and curing. It is easy to operate and can realize continuous and large-scale production; and the raw materials are PDMS and silica (sand), which are inexpensive and easy to promote and apply.

[0019] (2) The passive radiation cooling coating of this invention, applied to containers and electrolyte storage tanks, can effectively reflect most of the solar radiation energy, significantly reducing the heat absorbed by the container body, internal equipment, and electrolyte storage tanks, and efficiently emitting the accumulated heat in the form of long-wave infrared radiation using atmospheric window bands. The synergistic effect of these two aspects makes the surface temperature of the container shell and the internal environment, as well as the temperature of the electrolyte storage tank, significantly lower than that of the same facility without the coating, effectively suppressing the performance degradation and shortened service life of the vanadium redox flow battery system caused by high temperature.

[0020] (3) The passive cooling of this invention significantly reduces the heat load inside the container, greatly reduces the operating time and energy consumption of the air conditioning system or ventilation fan, reduces the operation and maintenance cost of the energy storage system, and improves the overall energy efficiency of the system. The electricity generated by the photovoltaic modules can be directly used for the auxiliary equipment of the battery system itself (such as circulation pumps and control systems), reducing dependence on the external power grid, or can be given priority to the load, forming a local photovoltaic-storage self-sufficient system, improving the system's economy and energy self-sufficiency. Detailed Implementation

[0021] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0023] Example 1: Preparation of ADS / PDMS cooling coating Step S1, ADS particle preparation: (1) Raw material preparation: Take 3g of 117nm monodisperse SDS silica nanoparticles and mix them with 97g of deionized water to prepare a 3% mass fraction dispersion. (2) Dispersion treatment: Place the dispersion in an ultrasonic cleaner and sonicate for 30 minutes while stirring at a high speed of 800 r / min until the particles are completely dispersed; (3) Spray drying: The dispersion was introduced into a small spray dryer, with the inlet temperature set to 120℃, the outlet temperature to 60℃, the feed rate to 3.3mL / min, the air flow rate to 357L / min, and the suction to 80%. The product was collected to obtain ADS particles. The ADS particles were tested and found to have a particle size of 3.0μm and an internal pore size of 2-20nm.

[0024] Step S2, Preparation of ADS / PDMS cooling coating: (1) Preparation of base adhesive: Take 100g of PDMS base adhesive and 10g of PDMS curing agent, mix and stir evenly, let stand for 15min to degas, and obtain PDMS mixed base adhesive; (2) Particle mixing: Add 5.25g of ADS particles (accounting for 5% of the mass of the base adhesive) to the PDMS mixed base adhesive, stir manually for 15min to obtain a uniform mixed slurry; (3) Coating film: After ultrasonicating the glass substrate with ethanol for 10 min, rinsing with deionized water and drying, pour on the mixed slurry and coat it with a scraper to form a film preform with a thickness of 600 μm; (4) Curing and molding: Place the substrate in an oven and heat it at 100°C for 2 hours. After cooling, peel it off to obtain the ADS / PDMS cooling coating.

[0025] Comparative Example 1: Preparation of SDS / PDMS Cooling Coating Step S1, SDS particle preparation: Monodisperse dense silica (SDS) nanoparticles with a particle size of approximately 117 nm are made directly from commercially available raw materials; the matrix is ​​polydimethylsiloxane (PDMS) and a matching curing agent.

[0026] Step S2, Preparation of SDS / PDMS cooling coating: (1) Preparation of base adhesive: Take 100g of PDMS base adhesive and 10g of PDMS curing agent, mix and stir evenly, let stand for 15min to degas, and obtain PDMS mixed base adhesive; (2) Particle mixing: Add 5wt% SDS particles (accounting for 5% of the base adhesive mass) to the PDMS mixed base adhesive, stir manually for 15 minutes to obtain a uniform mixed slurry; (3) Rod coating: The mixture is coated onto a flat glass substrate using the rod coating method, and the film thickness is controlled to be about 600 μm; (4) Curing and molding: Place in a 100 ℃ oven for 2 h to cure and obtain SDS / PDMS cooling coating.

[0027] Test Example 1: Morphology and Dispersion Characterization The particle morphology and internal dispersion state of the ADS / PDMS cooling coating prepared in Example 1 and the SDS / PDMS cooling coating prepared in Comparative Example 1 were observed using field emission scanning electron microscopy (FE-SEM) and focused ion beam scanning electron microscopy (FIB-SEM). It was observed that the SDS nanoparticles in the SDS / PDMS cooling coating were randomly distributed and prone to local aggregation, with uneven distribution of scattering centers and poor optical uniformity of the film. In contrast, the ADS micron-sized aggregates in the ADS / PDMS cooling coating had intact structures, were uniformly dispersed in PDMS, had well-organized scattering sites, and exhibited stable and consistent optical properties.

[0028] Test Example 2: Visible Light Transmittance (0.3-1.1 μm) Test The transmittance of crystalline silicon solar cells in the effective absorption band was tested using a UV-Vis spectrophotometer. The test results showed that the visible light transmittance (0.3-1.1 μm) of the SDS / PDMS cooling coating in Comparative Example 1 was approximately 65%, with significant backscattering loss; while the visible light transmittance (0.3-1.1 μm) of the ADS / PDMS cooling coating in Example 1 reached 70%, with near-field coupling and multiple scattering converting backscattering into forward scattering, ensuring efficient photovoltaic light collection.

[0029] Test Example 3: Near-infrared reflectance (1.1-2.5 μm) test Near-infrared reflectance was measured using a UV-Vis-NIR spectrophotometer with an integrating sphere. The test results showed that the near-infrared reflectance (1.1-2.5 μm) of the SDS / PDMS cooling coating in Comparative Example 1 was approximately 70%, primarily due to Rayleigh scattering, indicating weak long-wavelength thermal radiation blocking ability. In contrast, the near-infrared reflectance (1.1-2.5 μm) of the ADS / PDMS cooling coating in Example 1 was as high as 80%, triggering strong Mie scattering and multiple scattering at the micrometer scale, resulting in highly efficient reflection of solar thermal radiation.

[0030] Test Example 4: Infrared Emissivity (8-13 μm Atmospheric Window) Test The emissivity in the atmospheric transparent window band was measured using Fourier transform infrared spectroscopy (FTIR). The infrared emissivity (8-13 μm atmospheric window) of the SDS / PDMS cooling coating in Comparative Example 1 was 90.59%; while the infrared emissivity (8-13 μm atmospheric window) of the ADS / PDMS cooling coating in Example 1 was 91.24%. ADS did not reduce the intrinsic high emissivity of PDMS and can stably radiate heat into outer space.

[0031] In summary, compared with monodisperse SDS, which mainly relies on weak Rayleigh scattering, making it difficult to balance light transmission and heat insulation, and has poor dispersion and low near-infrared reflection efficiency, ADS achieves scattering mode regulation, light field orientation optimization and enhanced heat management through multi-level structural design. It simultaneously overcomes the performance contradiction between "high light transmission" and "forced cooling", enabling the composite film to achieve higher net cooling power, lower equilibrium temperature and better cooling effect under daytime solar irradiation, fundamentally improving the passive daytime radiation cooling performance.

[0032] Example 2: A Vanadium Redox Flow Battery Energy Storage System Integrating Photovoltaic Enhancement and Passive Radiation Cooling and Experiment In a 125kW vanadium redox flow battery energy storage project in Guangdong, a modular container (13000×2500×2600mm) and a 32m³ are used. 3The electrolyte storage tank system is equipped with a 15kW air conditioning refrigeration unit for thermal management; it adopts the refrigeration coating described in Example 1; and it uses 580W double-glass modules with dimensions of 2741×1134mm. To verify the effectiveness of this invention, it was implemented in three stages: (1) Photovoltaic efficiency enhancement experiment: An experiment was conducted on the top of a container to test the effect of the cooling coating's scattering light on the power generation of a double-glass module. A control experiment was set up to compare the power generation efficiency of the double-glass module before and after the cooling coating was applied. The specific implementation method is as follows: The cooling coating from Example 1 was completely applied to the top of a container, and a 580W monocrystalline silicon photovoltaic module was installed on top of it. The photovoltaic power generation effect before and after coating was compared. The specific test results are shown in Table 1 below: Table 1 Peak roof temperature Peak temperature of module backsheet Average daily power generation Efficiency improvement Uncoated group 64.4℃ 58℃ 417kWh - Coating group 40.2℃ 36℃ 465.7kWh 7.89% The data in Table 1 show that the peak temperature of the coated surface is 22°C lower than that of the uncoated area, which increases the power generation efficiency of the double-glass module array by 7.89% and increases the daily power generation by 48.7 kWh.

[0033] (2) Cooling test of energy storage equipment: An outdoor experiment was conducted to investigate the effect of a radiative cooling coating on the temperature of a container and an electrolyte storage tank. A control experiment was set up to compare the temperature changes on the outer surface of the container and tank before and after applying the cooling coating under the same weather conditions. To reduce the damage to the fuel cell stack and electrolyte caused by temperature rise, this experiment used empty containers and tanks. The experiment was conducted during the summer, with 7 consecutive sunny days and an average daily solar irradiance of 5.8 kWh / m². 2 The ambient temperature should be 32-38℃. The specific implementation method is as follows: Four PT1000 thermocouples were installed on the top and sides of the container, and two sensors were installed at the top, middle, and bottom of the storage tank. Three sensors were installed at the center point inside the container, and two sensors were installed 1 meter from the top and bottom of the storage tank. Sampling was performed every 10 minutes, with continuous recording from 06:00 to 18:00 daily.

[0034] Empty containers and storage tanks were placed outdoors for one day, and their temperature changes and peak values ​​were recorded. A cooling coating was applied to the outer surface of the containers and the outer surface of the electrolyte storage tank. The coated empty containers and storage tanks were then placed outdoors for one day, and their temperature changes and peak values ​​were recorded. Specific test results are shown in Table 2 below. Table 2 Table 2 shows that the high solar reflectivity of the coating reduced the solar radiation absorption rate of the container roof from 78% to 18%, and decreased the peak heat flux density by 1.6 kW / m². 2Empty storage tanks, lacking liquid heat capacity, exhibit a faster temperature response (delay of only 0.5 hours), yet the coating still significantly reduces thermal inertia. The temperature drop on the sides of the container (Δ18.1℃) is less than that on the top (Δ22.3℃) due to variations in the solar incidence angle on the vertical plane. The upper cavity of the tank (Δ19.2℃) experiences better temperature reduction than the lower cavity (Δ12.1℃), confirming thermal stratification caused by rising hot air. Experiments demonstrate that the cooling coating has a significant cooling effect on empty containers and empty storage tanks. The maximum temperature reduction on the outer surface reaches 22.3℃, while the average temperature reduction in the internal cavity is 14.4℃. The coating effectively blocks heat transfer paths through a dual mechanism of solar radiation reflection and infrared emission.

[0035] (3) Photovoltaic-storage integrated experiment: An outdoor experiment was conducted to test the feasibility of a cooling coating working in conjunction with a double-glass photovoltaic module to enhance the performance of an all-vanadium redox flow battery. The specific method is as follows: The outer surfaces of the vanadium redox flow battery container and electrolyte storage tank, especially the top and the side walls exposed to strong sunlight from the south / west, are coated with a radiative cooling coating. Eighteen 580W monocrystalline silicon photovoltaic modules (total power 10.44kW) are installed at 0.3m intervals on the top, forming a photovoltaic-coating composite cooling layer with the radiative cooling material on the module backsheet, preferentially driving key loads such as the air conditioner (15kW) and the circulation pump (3.2kW). The double-glass photovoltaic modules are fixedly installed above the container top via support frames, creating a ventilation gap between the bottom of the modules and the top of the container. This gap facilitates air circulation, removing heat from the container and the bottom of the photovoltaic panels. PT1000 thermocouples are installed at 16 points: four on each of the top and sides of the container, and two each on the upper, middle, and lower parts of the storage tank. Three sets of temperature sensors are arranged in layers inside the electrolyte storage tank, at distances of 0.5m, 1.5m, and 2.5m from the liquid surface, respectively. The air conditioner's operating status is recorded in real time by a smart meter (sampling interval of 5 minutes). The experiment was conducted during the summer, with seven consecutive sunny days and an average daily solar irradiance of 5.8 kWh / m². 2 The ambient temperature is 32-38℃.

[0036] The specific test results are shown in Table 3 below: Table 3 parameter Uncoated system Coating optimization system Optimization range Average daily air conditioning operating time 9.8 hours 5.2 hours -46.9% Daily energy consumption of air conditioners 127.3kWh 67.8kWh -46.7% Air conditioner condenser operating temperature 54℃ 41℃ Δ13℃ Peak temperature inside the chamber 42.1℃ 33.6℃ Δ8.5℃ Peak surface temperature of the enclosure 68.3℃ 45.1℃ Δ23.2℃ Temperature fluctuation standard deviation 3.8℃ 1.7℃ -55.3% Experimental data show that the coating fundamentally alters the thermodynamic behavior of the container surface, reducing the peak external surface temperature from 68.3℃ to 45.1℃, a decrease of 23.2℃. This effect stems from the coating's high reflectivity to the solar spectrum (absorption rate reduced from 78% to 18%), significantly weakening the initial driving force of heat conduction. The internal temperature response exhibits gradient optimization, with a 19.2℃ decrease in the top cavity temperature and a 12.1℃ decrease at the bottom, confirming that natural convection caused by rising hot air is effectively suppressed. The coating blocks approximately 82% of solar radiation heat (approximately 1.6 kW / m²).2 This significantly reduces the thermal inertia of the enclosure. The frequency of air conditioner start-stop decreases by 62%, the compressor operates under more stable conditions, the condensing temperature drops from 54℃ to 41℃, and the COP value increases by 39%.

[0037] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling, characterized in that, The system includes a vanadium redox flow battery container, positive and negative electrolyte storage tanks, an ADS / PDMS passive radiation cooling coating, photovoltaic double-glass modules, and a support and ventilation gap structure; the cooling coating is applied to the top of the container, the south / west-facing sidewalls, and the outer surface of the electrolyte storage tanks. The photovoltaic double-glass module is mounted on the top of the container via a bracket, with a ventilation gap maintained between it and the top surface of the container. The ADS / PDMS cooling coating uses PDMS as a substrate and is doped with aggregated dense silica particles, with a solar reflectance SR≥80%, an 8-13μm infrared emissivity ε≥91%, and a visible light transmittance ≥70%. The photovoltaic double-glass module is a bifacial power generation module, receiving direct sunlight on the front and reflected light from the cooling coating on the back, forming a photovoltaic-storage complementary system.

2. The all-vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling according to claim 1, characterized in that, The preparation method of the ADS / PDMS passive radiation cooling coating includes the following steps: Step S1, Preparation of ADS particles: Using nano-silica particles as raw materials and deionized water as the dispersion medium, prepare a nano-silica dispersion; sonicate and stir the prepared dispersion to disperse it; spray dry the dispersed liquid, and the nano-silica particles self-assemble and aggregate to form ADS particles. Collect the dried product to obtain ADS particles. Step S2, Preparation of ADS / PDMS passive radiation cooling coating: Mix PDMS base adhesive and PDMS curing agent, stir and let stand to degas, to obtain PDMS mixed base adhesive; add ADS particles to PDMS mixed base adhesive, stir manually to disperse, to obtain ADS / PDMS mixed slurry; pour ADS / PDMS mixed slurry onto substrate, and form film preform by scraping; heat to cure, cool and peel off film preform to obtain ADS / PDMS passive radiation cooling coating.

3. The all-vanadium redox flow battery energy storage system integrating photovoltaic efficiency enhancement and passive radiative cooling according to claim 2, characterized in that, In step S1, the nano-silica particles are monodisperse dense silica with a particle size of 117±5nm.

4. The all-vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling according to claim 2, characterized in that, In step S1, the mass fraction of the nano-silica dispersion is 1-5%.

5. The all-vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling according to claim 2, characterized in that, In step S1, during the spray drying process, the hot air outlet temperature is controlled at 60±5℃.

6. The all-vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling according to claim 2, characterized in that, In step S2, the mass fraction of the ADS particles in the PDMS mixed base adhesive is 3-7%.

7. The all-vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling according to claim 2, characterized in that, In step S2, the substrate is a glass substrate or a PET flexible substrate, which is ultrasonically cleaned with ethanol, rinsed with deionized water, and dried before use.

8. The all-vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling according to claim 1, characterized in that, The ventilation gap has a height of 0.2-0.5m to achieve natural convection heat dissipation.

9. The all-vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling according to claim 1, characterized in that, The photovoltaic double-glass modules are installed at the local latitude tilt angle, which increases power generation by ≥7.5% compared to single-sided modules. The generated power is prioritized for supplying system pumps, control units, and air conditioning, reducing dependence on the power grid.

10. The all-vanadium redox flow battery energy storage system integrating photovoltaic enhancement and passive radiative cooling according to claim 1, characterized in that, The photovoltaic double-glass module is connected to the vanadium redox flow battery system via an inverter. The generated power is used to assist system operation or to prioritize power supply to the load, forming a photovoltaic-storage complementary system.

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