Agriculture-light complementation device and photovoltaic agricultural system

Abstract

The application discloses a kind of agricultural light complementary device and photovoltaic agricultural system, it is related to photovoltaic agricultural technical field;The agricultural light complementary device includes support frame, is installed in planting area;Double-sided photovoltaic panel assembly is installed in the support frame;The double-sided photovoltaic panel assembly includes top light-receiving surface and bottom light-receiving surface oppositely arranged;Reflective photovoltaic panel assembly is installed in the support frame;The reflective photovoltaic panel assembly is located between the double-sided photovoltaic panel assembly and the planting area, and is spaced apart in height direction with the double-sided photovoltaic panel assembly, is staggered in horizontal direction and is set, so that at least part of the light area of the reflective photovoltaic panel assembly can receive sunlight from above and reflect it to the bottom light-receiving surface of the double-sided photovoltaic panel assembly;Specifically, the reflective photovoltaic panel assembly includes reflective functional area and photovoltaic functional area.The technical scheme provided by the application can effectively improve photovoltaic power generation efficiency.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic agricultural technology, and in particular to an agricultural-photovoltaic complementary device and a photovoltaic agricultural system. Background Technology

[0002] With the accelerated transformation of the global energy structure, the composite utilization model of "photovoltaics + agriculture" (i.e., photovoltaic agricultural system) has emerged. It is a composite project model that achieves efficient resource utilization by superimposing photovoltaic power generation and agricultural production on the same land space, and realizes three-dimensional development of power generation on the panel and planting on the ground by using agricultural photovoltaic complementary devices.

[0003] In the existing technology, the agricultural photovoltaic complementary device has not yet achieved the synergistic optimization of power generation efficiency and agricultural planting environment. The main technical problems are as follows: the bottom gain of the bifacial photovoltaic panel module mainly relies on the natural reflection of the ground (such as grassland, sand, cement ground) to increase the bottom power generation. However, the ground reflectivity is greatly affected by factors such as vegetation growth and dust accumulation, and the actual gain fluctuates drastically.

[0004] It should be noted that the above content is only used to help understand the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to propose an agricultural-photovoltaic complementary device and a photovoltaic agricultural system, which aims to effectively improve the efficiency of photovoltaic power generation.

[0006] To achieve the above objectives, the present invention proposes an agricultural-solar hybrid device, comprising: A support frame is installed on the planting area, whereby crops are grown. A bifacial photovoltaic panel module is installed on the supporting frame; the bifacial photovoltaic panel module includes a top light-receiving surface and a bottom light-receiving surface arranged opposite each other, the top light-receiving surface is used to absorb sunlight and perform photoelectric conversion; A reflective photovoltaic panel assembly is installed on the supporting frame. The reflective photovoltaic panel assembly is located between the bifacial photovoltaic panel assembly and the planting area, and is spaced apart from the bifacial photovoltaic panel assembly in the height direction and staggered in the horizontal direction, so that at least a portion of the light-receiving area of ​​the reflective photovoltaic panel assembly can receive sunlight from above and reflect it to the bottom light-receiving surface of the bifacial photovoltaic panel assembly. Specifically, the reflective photovoltaic panel assembly includes a reflective functional area and a photovoltaic functional area. The photovoltaic functional area is used to absorb sunlight and perform photoelectric conversion. The reflective functional area is used to reflect sunlight to the bottom light-receiving surface, so that the bottom light-receiving surface absorbs the reflected light from the reflective photovoltaic panel assembly and performs photoelectric conversion, and projects the unabsorbed light as reflected light or scattered light onto the planting area, so as to form a stepped light path of sunlight through the reflective photovoltaic panel assembly, the bottom light-receiving surface of the bifacial photovoltaic panel assembly, and the planting area.

[0007] In one embodiment, the bifacial photovoltaic panel assembly and / or the reflective photovoltaic panel assembly are lockably and rotatably connected to the support frame; the agricultural-photovoltaic complementary device includes a light-sensing tracking module, which is used to adjust the tilt angle of the bifacial photovoltaic panel assembly and / or the reflective photovoltaic panel assembly relative to the support frame according to the incident direction of sunlight and the direction of sunlight reflection.

[0008] In one embodiment, the horizontal projection areas of the reflective photovoltaic panel assembly and the bifacial photovoltaic panel assembly at least partially overlap, and the ratio of the horizontal projection area of ​​the reflective photovoltaic panel assembly to that of the bifacial photovoltaic panel assembly is 0.3 to 1.2.

[0009] In one embodiment, the reflective functional area and the photovoltaic functional area are in a stacked structure; specifically, the reflective functional area includes a semi-transparent reflective layer, and the photovoltaic functional area is disposed below or inside the semi-transparent reflective layer for absorbing sunlight that passes through the semi-transparent reflective layer.

[0010] In one embodiment, the reflective functional area is coated with a high reflectivity coating, the high reflectivity coating having an average solar spectral reflectivity of 60-85%; wherein, the high reflectivity coating is a fluorocarbon resin coating doped with titanium dioxide particles.

[0011] In one embodiment, the bifaciality of the bifacial photovoltaic panel module is 70-90%.

[0012] In one embodiment, the support frame includes a column, a first crossbeam, and a second crossbeam; the first crossbeam and the second crossbeam are fixedly connected to the column, the double-sided photovoltaic panel assembly is rotatably connected to the first crossbeam, and the reflective photovoltaic panel assembly is rotatably connected to the second crossbeam.

[0013] In one embodiment, the reflective photovoltaic panel assembly is made of a spectrally selective photovoltaic material, or its reflective functional area is provided with a spectrally selective reflective layer; the spectrally selective photovoltaic material or the spectrally selective reflective layer has an average reflectivity of not less than 60% for photons in the 500-600 nm and 700-900 nm wavelength bands, so that they are preferentially reflected to the bottom light-receiving surface of the bifacial photovoltaic panel assembly for power generation; and the average transmittance for photons in the 400-500 nm and 600-700 nm wavelength bands is not less than 50%, so that they are preferentially absorbed by the photovoltaic functional area and converted into photoelectric signals.

[0014] In one embodiment, a fluorescent down-conversion material is disposed in the reflective functional area of ​​the reflective photovoltaic panel assembly, the fluorescent down-conversion material being used to convert ultraviolet photons into 600-700 nm photons.

[0015] To achieve the above objectives, the present invention proposes a photovoltaic agricultural system, comprising several agricultural-photovoltaic complementary devices as described in any of the above claims.

[0016] The technical solution of this invention involves placing a reflective photovoltaic panel assembly between a bifacial photovoltaic panel assembly and the planting area, with the reflective panel assembly spaced apart vertically and staggered horizontally. It integrates a reflective functional area and a photovoltaic functional area. The photovoltaic functional area absorbs sunlight and performs photoelectric conversion, while the reflective functional area reflects sunlight to the bottom light-receiving surface of the bifacial photovoltaic panel assembly. This allows the bottom light-receiving surface to absorb reflected light from the reflective photovoltaic panel assembly and perform photoelectric conversion, eliminating the passive reliance on uncontrollable reflection from the planting area ground. This ensures the bottom light-receiving surface receives stable and continuous reflected light, significantly improving and stabilizing bottom power generation. Gain; furthermore, after the bottom light-receiving surface of the bifacial photovoltaic panel module absorbs reflected light to generate electricity, it projects some of the unabsorbed light onto the planting area in the form of reflected or scattered light. That is, the sunlight passes through the tiered light path of the reflective photovoltaic panel module, the bottom light-receiving surface of the bifacial photovoltaic panel module, and the planting area in sequence; with the bifacial photovoltaic panel module and the reflective photovoltaic panel module staggered in the horizontal direction, the crops are effectively protected from direct sunlight to withstand its drastic changes and light spot effects, providing crops with a softer and more uniform diffused light environment, realizing the coordinated distribution and tiered utilization of light energy for photovoltaic power generation and agricultural planting, and ultimately achieving the synergistic improvement of power generation efficiency and optimization of the planting light environment. Attached Figure Description

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

[0018] Figure 1 A schematic diagram of an embodiment of the agricultural-solar hybrid device provided by the present invention; Explanation of reference numerals in the attached figures: 10. Support frame; 11. Column; 12. First crossbeam; 13. Second crossbeam; 20. Double-sided photovoltaic panel module; 21. Top light-receiving surface; 22. Bottom light-receiving surface; 30. Reflective photovoltaic panel module; 40. Planting area; The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a portion of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, it should be noted that the descriptions involving "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0022] In the existing technology, the agricultural photovoltaic complementary device has not yet achieved the synergistic optimization of power generation efficiency and agricultural planting environment. The main technical problems are as follows: the bottom gain of the bifacial photovoltaic panel module mainly relies on the natural reflection of the ground (such as grassland, sand, cement ground) to increase the bottom power generation. However, the ground reflectivity is greatly affected by factors such as vegetation growth and dust accumulation, and the actual gain fluctuates drastically.

[0023] To address the aforementioned technical problems, this invention proposes an agricultural-solar hybrid device.

[0024] Please see Figure 1 In one embodiment of the present invention, the agricultural-solar hybrid device includes: A support frame 10 is installed on the planting area 40, whereby the planting area 40 is used for crop cultivation. A bifacial photovoltaic panel module 20 is installed on a support frame 10. The bifacial photovoltaic panel module 20 includes a top light-receiving surface 21 and a bottom light-receiving surface 22 arranged opposite to each other. The top light-receiving surface 21 is used to absorb sunlight and perform photoelectric conversion. A reflective photovoltaic panel assembly 30 is installed on the support frame 10. The reflective photovoltaic panel assembly 30 is located between the bifacial photovoltaic panel assembly 20 and the planting area 40, and is spaced apart from the bifacial photovoltaic panel assembly 20 in the height direction and staggered in the horizontal direction, so that at least part of the light-receiving area of ​​the reflective photovoltaic panel assembly 30 can receive sunlight from above and reflect it to the bottom light-receiving surface 22 of the bifacial photovoltaic panel assembly 20. Specifically, the reflective photovoltaic panel assembly 30 includes a reflective functional area and a photovoltaic functional area. The photovoltaic functional area is used to absorb sunlight and perform photoelectric conversion. The reflective functional area is used to reflect sunlight to the bottom light-receiving surface 22, so that the bottom light-receiving surface 22 absorbs the reflected light from the reflective photovoltaic panel assembly 30 for photoelectric conversion, and projects the unabsorbed light into the planting area 40 in the form of reflected light or scattered light, so as to form a stepped light path of sunlight through the reflective photovoltaic panel assembly 30, the bottom light-receiving surface 22 of the bifacial photovoltaic panel assembly 20 and the planting area 40.

[0025] The technical solution of this invention involves placing a reflective photovoltaic panel assembly 30 between a bifacial photovoltaic panel assembly 20 and a planting area 40, with the assembly spaced apart from the bifacial photovoltaic panel assembly 20 in the height direction and staggered in the horizontal direction. It integrates a reflective functional area and a photovoltaic functional area. The photovoltaic functional area absorbs sunlight and performs photoelectric conversion, while the reflective functional area reflects sunlight to the bottom light-receiving surface 22 of the bifacial photovoltaic panel assembly 20. This allows the bottom light-receiving surface 22 to absorb the reflected light from the reflective photovoltaic panel assembly 30 and perform photoelectric conversion, thus eliminating the passive reliance on uncontrollable reflection from the ground of the planting area 40. This ensures the bottom light-receiving surface 22 receives stable and continuous reflected light, significantly improving and stabilizing bottom power generation. Gain; and furthermore, after the bottom light-receiving surface 22 of the bifacial photovoltaic panel module 20 absorbs reflected light to generate electricity, it projects some of the unabsorbed light back onto the planting area 40 in the form of reflected or scattered light. That is, the sunlight passes through the tiered light path of the reflective photovoltaic panel module 30, the bottom light-receiving surface 22 of the bifacial photovoltaic panel module 20, and the planting area 40 in sequence. With the bifacial photovoltaic panel module 20 and the reflective photovoltaic panel module 30 staggered in the horizontal direction, the crops are effectively protected from direct sunlight to withstand its drastic changes and light spot effects, providing the crops with a softer and more uniform diffused light environment. This realizes the coordinated distribution and tiered utilization of light energy for photovoltaic power generation and agricultural planting, and ultimately achieves the coordinated improvement of power generation efficiency and optimization of the planting light environment.

[0026] The optical path design principle of this application is described in detail below: Lower layer reflection and initial power generation: Direct sunlight first shines on the side of the lower layer reflective photovoltaic panel module 30 away from the planting area 40; among them, part of the light penetrates the reflective functional area and is absorbed by the photovoltaic cells of the lower integrated photovoltaic functional area, generating the first photoelectric conversion; the other part of the light is reflected upward by the reflective functional area, forming a stable directional reflected beam.

[0027] Secondary power generation on the back of the upper layer: The reflected light beam from the lower layer is transmitted upward and reaches the bottom light-receiving surface 22 of the upper double-sided photovoltaic panel module 20, where it is absorbed and a second photoelectric conversion is generated; during this period, the top light-receiving surface 21 of the double-sided photovoltaic panel module 20 continuously absorbs direct sunlight for photoelectric conversion. Secondary reflection and scattering planting: Light that is not completely absorbed by the upper bottom light-receiving surface 22 is reflected a second time at the bottom of the upper double-sided photovoltaic panel module 20, and is projected downwards into the planting area 40 in the form of low-intensity, wide-range scattered light. After two reflections, the light intensity is moderate (about 10-30% of the intensity of direct sunlight), and the spectrum is mainly composed of scattered light, avoiding the high temperature of the soil surface and rapid evaporation of moisture caused by strong direct sunlight.

[0028] As a preferred embodiment of the above, the bifacial photovoltaic panel assembly 20 and / or the reflective photovoltaic panel assembly 30 are lockably and rotatably connected to the support frame 10. The agricultural-solar hybrid device includes a light-sensing tracking module, which is used to adjust the tilt angle of the bifacial photovoltaic panel assembly 20 and / or the reflective photovoltaic panel assembly 30 relative to the support frame 10 according to the direction of sunlight incidence and the direction of sunlight reflection. This lockable and rotatable connection means that the bifacial photovoltaic panel assembly 20 and / or the reflective photovoltaic panel assembly 30 and the support frame 10 can be angled through a rotating mechanism (such as a shaft, hinge, etc.), and can maintain a stable posture after adjustment to the target angle through a locking device (such as a locking nut, a worm gear self-locking structure, etc.), ensuring both the flexibility of dynamic light tracking and the system reliability under external forces such as wind loads. The light-tracking module is a closed-loop control system. It uses a light sensor to collect real-time data on the direction of sunlight incidence (i.e., solar altitude and azimuth angles) and the direction of sunlight after reflection from the reflective photovoltaic panel 30. Based on these parameters, it calculates the optimal tilt angle for the bottom light-receiving surface 22 of the bifacial photovoltaic panel 20 to receive the reflected light, and then drives actuators such as motors to adjust the tilt angle of the corresponding components. This feature enables active tracking and matching of the reflected light path—the bifacial photovoltaic panel 20 can dynamically rotate so that its bottom light-receiving surface 22 always faces the reflected beam from the reflective photovoltaic panel 30. Simultaneously, the reflective photovoltaic panel 30 can be independently adjusted to optimize the upward reflection directionality, thereby maximizing the back-side power generation gain under all-weather conditions. A lockable design ensures the long-term operational stability of the system. In this embodiment, the light-tracking system includes a four-quadrant photoelectric sensor and a controller. It collects solar azimuth and altitude angle data every 15 minutes to calculate the optimal tilt angle so that the bottom light-receiving surface faces the direction of the reflected beam from the lower layer.

[0029] As a preferred embodiment of the above, the horizontal projection areas of the reflective photovoltaic panel assembly 30 and the bifacial photovoltaic panel assembly 20 at least partially overlap, and the ratio of the horizontal projection area of ​​the reflective photovoltaic panel assembly 30 to the horizontal projection area of ​​the bifacial photovoltaic panel assembly 20 is 0.3 to 1.2. This configuration, where "the horizontal projection areas at least partially overlap," means that in the vertical projection direction, the horizontal projection areas of the reflective photovoltaic panel assembly 30 and the bifacial photovoltaic panel assembly 20 intersect. This ensures that the light reflected upwards from the reflective photovoltaic panel assembly 30 can be effectively projected into the bottom light-receiving surface 22 of the bifacial photovoltaic panel assembly 20, meaning that the middle layer reflected light can be received by the upper bottom light-receiving surface 22. The ratio of the horizontal projection area to the vertical projection area is 0.3 to 1.2, which is a quantitative limit on the ratio of the two projection areas. If the ratio is less than 0.3, it means that the area of ​​the reflective photovoltaic panel 30 is too small, and the amount of solar flux it can capture and reflect upward is insufficient, making it difficult to effectively improve the power generation gain at the bottom of the bifacial photovoltaic panel 20. At the same time, the power generation contribution of its own photovoltaic functional area is also relatively limited. If the ratio is greater than 1.2, the area of ​​the reflective photovoltaic panel 30 is too large. On the one hand, it will exceed the range of the bottom light-receiving surface 22 of the bifacial photovoltaic panel 20, causing some reflected light to be wasted because it cannot be received by the upper layer. On the other hand, the lower reflective photovoltaic panel 30 may have an adverse effect on the ventilation and heat dissipation of the bottom of the upper layer, and the excessively large lower panel may cause unnecessary over-regulation of the light reaching the planting area 40. Limiting the ratio to the range of 0.3 to 1.2 allows the system to achieve the optimal balance between unobstructed front lighting, matching the reflected light flux with the bottom light-receiving area of ​​the upper layer, and the power generation of the lower layer itself. Combining the aforementioned staggered arrangement and height interval, the area ratio range ensures that at least part of the light-receiving area of ​​the reflective photovoltaic panel module 30 can be exposed to direct sunlight (located outside the upper projection), while its reflected light path can effectively cover the bottom light-receiving surface 22 of the upper double-sided photovoltaic panel module 20, thereby forming a complete tiered light path of "sunlight → reflective photovoltaic panel module 30 (reflection + power generation) → bottom light-receiving surface 22 of double-sided photovoltaic panel module 20 (backside power generation + secondary reflection) → planting area 40", realizing the three-dimensional spatial synergistic utilization of "middle layer reflective power generation, upper layer backside power generation, and lower layer scattering planting" on the same land.

[0030] As a preferred embodiment of the above, the reflective functional area and the photovoltaic functional area are arranged in a stacked structure. Specifically, the reflective functional area includes a semi-transparent reflective layer, and the photovoltaic functional area is disposed below or inside the semi-transparent reflective layer to absorb sunlight transmitted through the semi-transparent reflective layer. This "stacked structure" means that the reflective functional area and the photovoltaic functional area are arranged in a vertically stacked manner in the thickness direction. In this structure, the semi-transparent reflective layer is disposed on the top layer, and its core optical characteristic is "semi-transparent and semi-reflective," meaning that a portion of the incident sunlight is reflected back upwards by this layer (fulfilling the function of the reflective functional area), while the other portion passes through this layer and enters the photovoltaic functional area below or inside it (fulfilling the function of the photovoltaic functional area). Distributing the photovoltaic functional area below or inside the semi-transparent reflective layer means that the transmitted light through the semi-transparent reflective layer can be immediately absorbed by the photovoltaic cell layer below and converted into photoelectric energy, thereby efficiently utilizing the remaining unreflected light energy and avoiding secondary loss of light energy. This arrangement has the following advantages: First, the reflectivity and transmittance of the semi-transparent reflective layer can be precisely matched through film design and thickness control, enabling flexible optimization of light energy distribution between upward reflection for power generation on the upper back and downward transmission for power generation on its own. Second, the reflective surface continuously covers the entire surface of the composite panel, eliminating gaps between functional zones and resulting in a more uniform distribution of reflected light, which is beneficial for uniform light reception on the bottom light-receiving surface of the upper double-sided photovoltaic module. Third, the semi-transparent reflective layer itself can also serve as a protective encapsulation layer for the upper surface of the photovoltaic functional area, providing dustproof, moisture-proof, and UV-resistant protection, simplifying the overall structure and reducing manufacturing costs.

[0031] As a preferred embodiment of the above, the reflective functional area is coated with a high-reflectivity coating, the high-reflectivity coating having an average solar spectral reflectivity of 60-85%; wherein, the high-reflectivity coating is a fluorocarbon resin coating doped with titanium dioxide particles. In this configuration, the high-reflectivity coating refers to a functional coating applied to the upper surface of the reflective photovoltaic panel assembly 30 (i.e., the side away from the planting area 40), its core function being to efficiently reflect incident sunlight upwards to the bottom light-receiving surface 22 of the bifacial photovoltaic panel assembly 20. An average solar spectral reflectance of 60-85% is a quantitative limit for the optical performance of this coating: when the reflectance is below 60%, the upward reflected light flux is insufficient, making it difficult to significantly improve the bottom power generation gain of the bifacial photovoltaic panel module 20; when the reflectance is above 85%, although the reflection performance is better, it means that the transmitted light penetrating the coating to enter the photovoltaic functional area below for power generation is reduced accordingly, which will reduce the photovoltaic power generation output of the reflective photovoltaic panel module 30 itself, and the material cost and manufacturing difficulty of the high reflectance coating will increase significantly; controlling the reflectance within the range of 60-85% can achieve the optimal energy distribution balance between upward reflection for power generation of the upper layer and downward transmission for power generation of the module itself. The fluorocarbon resin coating doped with titanium dioxide particles provides a specific material solution: fluorocarbon resin, as the film-forming matrix, has excellent weather resistance, UV aging resistance, and self-cleaning properties, and can maintain stable reflectivity in outdoor environments for a long time without easily chalking or yellowing; titanium dioxide (TiO2) particles, as high refractive index scattering centers, are uniformly dispersed in the fluorocarbon resin matrix, and their high refractive index characteristics can effectively enhance the diffuse reflection capability of the coating. At the same time, titanium dioxide itself has good absorption and scattering effects on ultraviolet light, which can protect the underlying photovoltaic materials from UV degradation.

[0032] As a preferred embodiment of the above, the bifaciality of the bifacial photovoltaic module 20 is 70% to 90%. Here, bifaciality refers to the percentage ratio of the bottom power generation efficiency to the top power generation efficiency of the bifacial photovoltaic module 20, a core indicator for evaluating the performance of bifacial photovoltaic technology. Limiting the bifaciality to 70% to 90% means that when the front side of the module receives 100 units of light energy and can generate 100 units of electrical energy, its back side can generate 70 to 90 units of electrical energy under the same light energy conditions. The selection of this numerical range has significant technical implications: if the bifaciality is below 70%, even if the reverse-order light path design of this invention provides sufficient reflected light to the back side, the power generation gain on the back side will be limited by the module's own conversion capability, failing to fully utilize the technical advantages of the active reflection light path.

[0033] As a preferred embodiment of the above, the support frame 10 includes a column 11, a first crossbeam 12, and a second crossbeam 13. The first crossbeam 12 and the second crossbeam 13 are fixedly connected to the column 11, the double-sided photovoltaic panel assembly 20 is rotatably connected to the first crossbeam 12, and the reflective photovoltaic panel assembly 30 is rotatably connected to the second crossbeam 13. With this configuration, the support frame 10 consists of three parts: the column 11, the first crossbeam 12, and the second crossbeam 13. The column 11 serves as a vertical load-bearing component, its bottom fixed to the ground or foundation piles, providing stable vertical support for the entire device. The first crossbeam 12 and the second crossbeam 13 are respectively fixedly connected to different height positions of the column 11, forming two independent horizontal installation interfaces. The rotatable connection of the bifacial photovoltaic panel module 20 to the first crossbeam 12 means that the upper bifacial photovoltaic panel module 20 is mounted on the first crossbeam 12 via a rotating mechanism such as a shaft, bearing, or rotary reducer, allowing it to rotate freely within a range of 0° to 180° around a horizontal axis. Similarly, the rotatable connection of the reflective photovoltaic panel module 30 to the second crossbeam 13 means that the lower reflective photovoltaic panel module 30 is mounted on the second crossbeam 13 via an independent rotating mechanism, also possessing angle adjustment capability. The core feature of this design is that the first crossbeam 12 and the second crossbeam 13 are independent fixed structures, with the bifacial photovoltaic panel module 20 and the reflective photovoltaic panel module 30 rotatably connected to their respective crossbeams, and there is no rigid linkage mechanism between them. This independent connection design has the following advantages: First, the upper and lower modules can independently adjust their tilt angles; the upper module can focus on tracking the optimal receiving angle of the reflected light from the lower module, while the lower module can independently optimize its own reflection posture or light-gathering angle, without interfering with each other. Second, the relative angle relationship between the upper and lower modules can be flexibly adjusted according to different seasons, time of day, and agricultural needs.

[0034] As a preferred embodiment of the above, the reflective photovoltaic panel assembly 30 is made of a spectrally selective photovoltaic material, or its reflective functional area is provided with a spectrally selective reflective layer; the average reflectivity of the spectrally selective photovoltaic material or the spectrally selective reflective layer for photons in the 500–600 nm and 700–900 nm wavelength bands is not less than 60%, and the average transmittance for photons in the 400–500 nm and 600–700 nm wavelength bands is not less than 50%. With this configuration, this feature provides two parallel implementation schemes: first, the reflective photovoltaic panel assembly 30 is entirely made of a spectrally selective photovoltaic material, that is, the material itself has differentiated absorption, reflection, and transmission characteristics for photons of different wavelengths; second, a spectrally selective reflective layer is provided on the surface of the reflective functional area of ​​the reflective photovoltaic panel assembly 30, and selective modulation of different wavelength bands is achieved through film interference effect. The core optical parameters of the two schemes mentioned above are: an average reflectivity of not less than 60% for the 500~600 nm (green light) and 700~900 nm (near infrared) bands, so that the light is preferentially reflected to the bottom light-receiving surface 22 of the double-sided photovoltaic panel module 20 for power generation; and an average transmittance of not less than 50% for the 400~500 nm (blue light) and 600~700 nm (red light) bands, so that the light is preferentially absorbed by the photovoltaic functional area and converted into photoelectric light. The scientific basis for this spectral modulation logic lies in the fact that green and near-infrared light bands are bands with low photosynthetic efficiency for crops. The molar extinction coefficient of chlorophyll at green light is only one-fifth to one-quarter of that at red and blue light, and near-infrared light basically does not participate in photosynthesis. However, these two bands happen to be the bands with good response of silicon-based photovoltaic cells, thus allowing them to be preferentially absorbed by the photovoltaic functional area and undergo photoelectric conversion. Conversely, blue and red light bands are the most efficient photosynthetic bands required for crop photosynthesis. Chlorophyll a has significant absorption peaks at blue light (approximately 430 nm) and red light (approximately 662 nm). Therefore, this feature preferentially reflects green and near-infrared light to the bottom light-receiving surface 22 of the bifacial photovoltaic panel module 20 for power generation, and transmits the unabsorbed red and blue light downwards to the planting area 40 for crop photosynthesis, thereby achieving spectral decoupling of power generation using waste and planting using what is needed on the same device. This feature fundamentally solves the contradiction between photovoltaic panels and crops competing for the effective spectrum in agricultural photovoltaic complementary systems, increasing the proportion of red and blue light in the photosynthetically effective radiation at the bottom of the panel from less than 50% in traditional systems to more than 80%, and increasing the net photosynthetic rate of crops by 15% to 30%. At the same time, the photovoltaic power generation efficiency does not decrease but increases, achieving a win-win situation for power generation and planting.

[0035] As a preferred embodiment of the above, the reflective photovoltaic panel module 30 is provided with a fluorescent down-conversion material in its reflective functional area. The fluorescent down-conversion material is used to convert ultraviolet photons into photons in the 600-700 nm wavelength range. Specifically, the fluorescent down-conversion material is a type of functional material with photoluminescence properties (such as rare-earth-doped phosphors, quantum dots, etc.). Its working principle follows the physical process of fluorescent down-conversion: the material absorbs a high-energy (short-wavelength) photon, such as an ultraviolet photon (about 300-400 nm), and then emits a low-energy (long-wavelength) photon, specifically a red photon in the 600-700 nm wavelength range in this feature. The scientific basis for this design is as follows: First, ultraviolet photons pose a potential risk of photodamage to plant leaves, potentially causing chlorophyll degradation and DNA damage, while contributing little to the power generation of silicon-based photovoltaic cells (the spectral response peak of silicon cells is around 600-900 nm, and the response efficiency in the ultraviolet region is significantly low). Second, the 600-700 nm red light band happens to be the core absorption band for crop photosynthesis (the main absorption peak of chlorophyll a at 662 nm), and it is also the band with good response of silicon-based photovoltaic cells. Therefore, by converting harmful and inefficient ultraviolet photons into highly efficient and usable red photons, this feature achieves the value-added conversion of harmful light into beneficial light. The converted red photons have two possible propagation paths: they enter the bottom light-receiving surface 22 of the bifacial photovoltaic panel module 20 via a reflection path for back-side power generation, or they enter the planting area 40 via a transmission path to promote crop photosynthesis. This feature further enhances the full-spectrum utilization of the solar spectrum, converting previously wasted or harmful ultraviolet energy into effective energy that can be used for both power generation and planting. At the same time, it reduces the risk of crop burn from ultraviolet radiation and has a significant crop protection effect in areas with strong ultraviolet radiation in summer. In addition, the increase in 600-700 nm red light helps improve the photomorphogenesis of crops (such as thicker stems, thicker leaves, and promotion of flowering and fruiting), further improving crop quality and yield.

[0036] The inventive advantages of this application are described below in conjunction with the above embodiments: (1) A fundamental subversion of the direction of light path All existing double-layer photovoltaic structures follow the optical path direction of "sunlight → upper front-side power generation → transmission → lower layer reflection → upper back-side power generation." The reflected light path is a supplement to the residual light path, and the back-side gain is passive and unstable. This application is the first to adopt a reverse-order design of "sunlight → lower layer reflection → upper back-side power generation → secondary reflection → substrate planting," placing the reflected light path at the front as the dominant light path. The upper back-side changes from "passively receiving ambient scattered light" to "actively receiving directional reflected light," achieving an order-of-magnitude improvement in back-side irradiance and stability.

[0037] (2) Coupling innovation of functional structure In existing technologies, reflectors / reflective panels are purely passive optical elements and do not have power generation capabilities; moreover, the reflector and photovoltaic panel are separate structures. The lower-layer reflective photovoltaic panel assembly of this invention breaks through the traditional understanding that "reflector = non-power generator," integrating a high-reflectivity coating and photovoltaic cells onto the same panel, achieving dual functionality: the upper surface reflects and controls the light path, while the lower surface / internal surface generates electricity, significantly improving functional coupling and space utilization efficiency.

[0038] (3) Reverse reconstruction of spatial arrangement Existing double-layer structures all use an arrangement of "upper layer photovoltaic panels and lower layer reflectors," with the lower reflector located near the ground or directly below the upper layer, severely compressing or eliminating the planting space underneath. This invention adopts an arrangement where "lower layer reflective photovoltaic panels are located in the middle, and upper layer double-sided photovoltaic panels are located on top," with the lower layer staggered from the upper layer. The planting area is located below, forming a clear three-dimensional functional partition of "upper power generation - middle reflection - lower planting," ensuring effective light path control while leaving ample space for agricultural planting.

[0039] (4) System-level improvement of optical path controllability Existing bifacial photovoltaic (PV) modules rely on ground reflection for their back-side light path, constituting an open-loop system highly susceptible to environmental disturbances. This application constructs a closed-loop internal light path through two reflections from the upper and lower PV panels. Reflectivity, reflection angle, and scattering characteristics can be precisely controlled by parameters such as coating materials, inter-panel distance, and tilt angle design, resulting in controllable light energy distribution. Simultaneously, by controlling the projection direction of the secondary reflected light, a linkage between "power generation optimization" and "agricultural light regulation" is achieved.

[0040] (5) Deep optimization of agricultural adaptability Existing research on photovoltaic-agricultural integration mainly focuses on planting experiments under fixed photovoltaic panels or simple tracking systems, failing to integrate tracking, bifaciality, reflection, and planting into a unified structural design. This invention, through a reverse-order light path design, ensures that the planting area receives softly scattered light after two reflections, eliminating the direct light spot effect. Simultaneously, the upper bifacial photovoltaic panel module acts as a "light path control node," its rotation angle mapping to the light distribution under the panel. This allows for the achievement of spatiotemporal uniformity of light under the panel through control algorithms, realizing for the first time a photovoltaic-agricultural synergy mechanism of "dynamic light tracking without disturbing agriculture and precise nutrient absorption through reflected residual light."

[0041] The following specific implementation scenario is simulated in conjunction with the above embodiments: Simulation Scenario 1: Standard Agricultural Photovoltaic Complementary Scenario Direct sunlight first illuminates the high-reflectivity coating on the upper surface of the lower reflective photovoltaic panel module. Approximately 25% of the light energy penetrates the coating and is absorbed by the integrated photovoltaic cells below, resulting in the first photoelectric conversion; approximately 70% of the light energy is reflected upwards by the high-reflectivity coating, forming primary reflected light. This primary reflected light travels upwards to the bottom light-receiving surface of the upper bifacial photovoltaic panel module, where it is absorbed by the back of the bifacial structure to generate electricity (second photoelectric conversion), and simultaneously undergoes a second reflection, forming secondary reflected light. This secondary reflected light is then evenly distributed to the planting area at the bottom of the panel in a scattered manner, meeting the photosynthetic needs of most leafy vegetables.

[0042] Rotation control logic: At noon, when the solar altitude angle is high, the upper bifacial photovoltaic panel is adjusted to a larger tilt angle (60~80°) so that the bottom light-receiving surface faces the reflected beam from the lower reflective photovoltaic panel above. In the morning or evening, when the solar altitude angle is low, the upper bifacial photovoltaic panel is adjusted to a smaller tilt angle (10~30°) to simultaneously receive reflected beams from the lower reflective photovoltaic panel on the side and scattered skylight. The light-sensing tracking module has a rotation range of 180°, covering all-weather light tracking needs from east-facing twilight to west-facing twilight.

[0043] Simulation Scenario 2: Optimization Scheme for High-Latitude Regions In high-latitude regions (above 40°N), to adapt to the difference in solar altitude angles between summer and winter, the tilt angle of the lower-layer reflective photovoltaic (PV) panels is seasonally adjustable: 15° in summer and 45° in winter, to enhance the efficiency of upward reflection of low-angle sunlight in winter. The rotation control program of the upper-layer bifacial PV panels uses seasonal parameter correction, with a target tilt angle of 50-60° at noon in winter to maximize the reception of reflected beams from the lower-layer PV panels. The planting area can be covered with an insulating film in winter, working together with the upper bifacial PV panels to create a greenhouse effect.

[0044] Simulation Scenario 3: Water-saving planting solutions in arid regions In arid and low-rainfall regions, the light reflection regulation function of this invention is combined with water-saving irrigation. Because the planting area at the bottom of the panel receives soft, diffused light that has undergone two reflections, the soil surface temperature is 5-8°C lower than that of bare ground, and soil moisture evaporation is reduced by more than 30%. Combined with a drip irrigation system, water savings of 40-50% can be achieved. The high-reflectivity coating of the lower reflective photovoltaic panel module has its reflectivity adjusted to 65%, further reducing the light intensity at the bottom of the panel, making it suitable for planting drought- and shade-tolerant medicinal herbs such as astragalus and licorice.

[0045] Simulation Scenario 4: Spectral Decoupling Reverse-Sequence Agricultural Photovoltaic Complementary System The lower reflective photovoltaic panel module uses a semi-transparent organic photovoltaic (ST-OPV) film as the substrate, and the active layer is a PM6:Y6 system. By adjusting the thickness of the active layer (about 100 nm) and the sheet resistance of the transparent electrode (indium tin oxide, ITO), its average transmittance in the 400~500 nm blue light band and the 600~700 nm red light band is ≥55% (preferentially transmitted to the bottom of the panel), and its average absorption rate in the 500~600 nm green light band and the 700~900 nm near-infrared band is ≥70% (preferentially reflected to the upper back for power generation).

[0046] The upper surface of the lower reflective photovoltaic panel module is coated with a SiO2 / TiO2 double-layer interference film as a wavelength-selective optical coating by magnetron sputtering. The film structure is designed with a center reflectivity of ≥65% in the 500~600 nm wavelength band and an average transmittance of ≥75% in the 400~500 nm and 600~700 nm wavelength bands. Actual measurements show that under direct midday sunlight, approximately 30% of the incident light is absorbed by the lower photovoltaic cells to generate electricity; approximately 25% of the green light is reflected upwards by the coating to the bottom of the upper bifacial photovoltaic panel module, where it is absorbed by the back side, adding an additional 10~15% gain to back-side power generation; approximately 35% of the red and blue light directly transmits through the lower substrate to the planting area at the bottom of the panel, with the remainder being lost through scattering.

[0047] Lettuce was planted in the planting area at the bottom of the substrate. The spectral composition of the substrate was measured using a spectroradiometer: blue light (400–500 nm) and red light (600–700 nm) accounted for 80% of the photosynthetically active radiation (PAR), significantly higher than that of traditional fixed-location photovoltaic systems (approximately 45–55%). The total PAR was 200 μmol·m⁻¹. -2 ·s -1 Under these conditions, the net photosynthetic rate of lettuce leaves increased by about 25% compared to the control group (with the same total PAR under traditional opaque photovoltaic panels), and the dry matter accumulation increased by about 20%.

[0048] As an alternative, wavelength-selective optical coatings can also be made with Sr2Si5N8:Eu. 2+ The red phosphor is encapsulated in a polydimethylsiloxane (PDMS) layer. This fluorescent downconversion material can convert 300-400 nm ultraviolet photons into approximately 620 nm red photons with a conversion efficiency of about 35%. In summer when ultraviolet radiation is strong, the photon flux density near 620 nm in the planting area under the board increases by about 15% additionally, while reducing the risk of ultraviolet radiation scorching lettuce leaves.

[0049] This invention also discloses a photovoltaic agricultural system, including several agricultural-photovoltaic complementary devices according to any of the above embodiments. The specific structure of the agricultural-photovoltaic complementary devices can be referred to the above embodiments. Since this photovoltaic agricultural system adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0050] It should be noted that the agricultural-photovoltaic complementary device and other contents of the photovoltaic agricultural system disclosed in this invention are prior art and will not be described in detail here.

[0051] The above are merely optional embodiments of the present invention and do not limit the patent scope of the present invention. Any application of the present invention directly or indirectly in other related technical fields is included within the patent protection scope of the present invention.

Claims

1. A solar-agricultural hybrid device, characterized in that, include: A support frame is installed on the planting area, whereby crops are grown. A bifacial photovoltaic panel module is installed on the supporting frame; the bifacial photovoltaic panel module includes a top light-receiving surface and a bottom light-receiving surface arranged opposite each other, the top light-receiving surface is used to absorb sunlight and perform photoelectric conversion; A reflective photovoltaic panel assembly is installed on the supporting frame. The reflective photovoltaic panel assembly is located between the bifacial photovoltaic panel assembly and the planting area, and is spaced apart from the bifacial photovoltaic panel assembly in the height direction and staggered in the horizontal direction, so that at least a portion of the light-receiving area of ​​the reflective photovoltaic panel assembly can receive sunlight from above and reflect it to the bottom light-receiving surface of the bifacial photovoltaic panel assembly. Specifically, the reflective photovoltaic panel assembly includes a reflective functional area and a photovoltaic functional area. The photovoltaic functional area is used to absorb sunlight and perform photoelectric conversion. The reflective functional area is used to reflect sunlight to the bottom light-receiving surface, so that the bottom light-receiving surface absorbs the reflected light from the reflective photovoltaic panel assembly and performs photoelectric conversion, and projects the unabsorbed light as reflected light or scattered light onto the planting area, so as to form a stepped light path of sunlight through the reflective photovoltaic panel assembly, the bottom light-receiving surface of the bifacial photovoltaic panel assembly, and the planting area. The reflective photovoltaic panel assembly is made of a spectrally selective photovoltaic material, or its reflective functional area is provided with a spectrally selective reflective layer; the spectrally selective photovoltaic material or the spectrally selective reflective layer has an average reflectivity of not less than 60% for photons in the 500-600 nm and 700-900 nm wavelength bands, and an average transmittance of not less than 50% for photons in the 400-500 nm and 600-700 nm wavelength bands.

2. The agricultural-solar hybrid device as described in claim 1, characterized in that: The bifacial photovoltaic panel assembly and / or the reflective photovoltaic panel assembly are lockably and rotatably connected to the support frame; the agricultural-photovoltaic complementary device includes a light-sensing tracking module, which is used to adjust the tilt angle of the bifacial photovoltaic panel assembly and / or the reflective photovoltaic panel assembly relative to the support frame according to the incident direction of sunlight and the direction of sunlight reflection.

3. The agricultural-solar hybrid device as described in claim 1, characterized in that: The horizontal projection areas of the reflective photovoltaic panel assembly and the bifacial photovoltaic panel assembly at least partially overlap, and the ratio of the horizontal projection area of ​​the reflective photovoltaic panel assembly to that of the bifacial photovoltaic panel assembly is 0.3 to 1.

2.

4. The agricultural-solar hybrid device as described in claim 1, characterized in that: The reflective functional area and the photovoltaic functional area are in a stacked structure; specifically, the reflective functional area includes a semi-transparent reflective layer, and the photovoltaic functional area is disposed below or inside the semi-transparent reflective layer for absorbing sunlight that passes through the semi-transparent reflective layer.

5. The agricultural-solar hybrid device as described in claim 1, characterized in that: The reflective functional area is coated with a high reflectivity coating, the high reflectivity coating having an average solar spectrum reflectivity of 60-85%; wherein, the high reflectivity coating is a fluorocarbon resin coating doped with titanium dioxide particles.

6. The agricultural-solar hybrid device as described in claim 1, characterized in that: The bifaciality of the bifacial photovoltaic panel module is 70-90%.

7. The agricultural-solar hybrid device as described in claim 1, characterized in that: The support frame includes a column, a first crossbeam, and a second crossbeam; the first crossbeam and the second crossbeam are fixedly connected to the column, the double-sided photovoltaic panel assembly is rotatably connected to the first crossbeam, and the reflective photovoltaic panel assembly is rotatably connected to the second crossbeam.

8. The agricultural-solar hybrid device as described in any one of claims 1 to 7, characterized in that: The reflective photovoltaic panel assembly has a fluorescent down-conversion material disposed in the reflective functional area, which is used to convert ultraviolet photons into 600-700 nm photons.

9. A photovoltaic agricultural system, characterized in that: It includes several agricultural-photovoltaic complementary devices as described in any one of claims 1 to 8.

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