Solar module with passive cooling structure and method of manufacturing and use thereof

Abstract

This application provides a solar module, its manufacturing method, and its uses. The solar module includes a front glass and a rear glass, which are fixedly connected to each other by at least one intermediate layer. A plurality of solar cells connected in series are disposed between the front and rear glass. A passive cooling structure with one or more cooling elements is disposed on the surface of the rear glass away from the plurality of solar cells. The passive cooling structure has a contact surface at which it is in thermal contact with the rear glass for heat conduction. The contact surface (13) covers at least 90% of the photovoltaic active surface of the solar module (1). The area ratio of the surface of the passive cooling structure away from the rear glass to the contact surface is at least 3. Each of the one or more cooling elements is made of a material having a thermal conductivity to density ratio of at least 0.02 W·cm⁻¹. 2 / (g·K); the surface density of the passive cooling structure (7) is less than 0.6 g / cm³. 2 The mass surface density is the mass of the passive cooling structure (7) per unit contact area; the resistivity surface product of the passive cooling structure (7) is greater than 4 × 10⁻⁶. 11 ohm·cm 2 The resistivity product is the product of the contact area between the passive cooling structure (7) and the rear glass (3) and the electrical contact resistance.

Description

Technical Field

[0001] This application relates to the field of solar energy technology, and more specifically to a solar module with a passive cooling structure, its manufacturing method, and its uses. Background Technology

[0002] Photovoltaic layer systems used in the production of solar cells are well known to those skilled in the art, for example, through commercially available solar modules. The materials of the layers in the system, especially the semiconductor materials of the absorber layers used for photoelectric conversion, are selected so that incident sunlight can be converted into electric current with satisfactory efficiency. Absorber layers formed from amorphous, microcrystalline, or polycrystalline silicon, cadmium telluride (CdTe), gallium arsenide (GaAs), copper indium gallium sulfide selenide (Cu(In,Ga)(S,Se)2), copper-zinc-tin-sulfonyl-selenide (CZTS from the chalcopyrite group), and organic semiconductors are particularly suitable for (thin-film) solar cells due to their physical properties and technical operability. The pentagonal semiconductor Cu(In,Ga)(S,Se)2, belonging to the chalcopyrite compound semiconductor group, is particularly important in the industrial mass production of solar modules.

[0003] In practical applications, solar modules can be installed on the roof of a building (roof mounting) or formed as part of the roof skin (interior roof mounting). It is also known that solar modules are used as facade or wall elements in building-integrated photovoltaics (BIPV), and in the form of freestanding or self-supporting (carrier-free) glass structures.

[0004] In solar modules, only a portion of the incident sunlight is converted into electricity, while the remainder is directly converted into heat. The heating of a solar module depends on external factors (such as ambient temperature and wind speed) and the specific structure of the module. Particularly in building-integrated solar modules, excessive heat generation can occur if the heat generated cannot be adequately dissipated. Uncontrolled heat output to the building facade is undesirable, as the building will be unacceptably heated in summer. Typically, insulation layers are present on the ventilated facades of buildings to provide adequate insulation during winter.

[0005] Furthermore, during operation, the electrical output of the solar module decreases as the internal temperature of the solar module and semiconductor structure increases. This characteristic of the solar module is described by a temperature coefficient Tk, which indicates the relative change in efficiency or electrical output (expressed as a percentage) with temperature (expressed in K). The temperature coefficient Tk depends primarily on the semiconductor structure used, varying, for example, between -0.4% / K (solar modules made of crystalline or polycrystalline silicon) and -0.28% / K (CdTe solar modules). The temperature coefficient for Cu(In,Ga)(S,Se)2-based solar modules is typically around -0.35% / K. For example, with a temperature increase of 40K, the electrical output decreases by 14% relative to the previous output.

[0006] The temperature rise of a solar module during operation can be simplified using the following formula:

[0007] T cell =T amb +1 / U×(α×G inc ×(1-η(T cell )))

[0008] in:

[0009] η(T cell )=η(25℃)×(1+δ×(T cell -25℃)

[0010] T amb Ambient temperature

[0011] G inc Radiated power

[0012] α: Absorption coefficient of solar radiation, i.e. (1-reflection)

[0013] η: Efficiency (describes the energy extracted from the solar module)

[0014] δ: Relative temperature coefficient of efficiency

[0015] U: Heat transfer coefficient

[0016] The heat transfer coefficient U depends on the thermal volume properties (thermal conductivity) of the solar module and the heat transfer to the environment (heat transfer coefficient). The heat transfer coefficient is further divided into a conductive component and a radiative component, which depend on the external wind speed. The reciprocal of the heat transfer coefficient U is the heat transfer resistance RT.

[0017] The above formula shows that improving electrical efficiency reduces heat loss, thereby reducing temperature rise. However, improving electrical efficiency requires significant technical effort and the increase is relatively small. Even increasing the solar module efficiency from 15% to 20% only results in a 6% decrease in heat energy. Furthermore, the absorption coefficient α of incident sunlight should not be reduced, as this would decrease the overall efficiency and output of the solar module. Improving the heat transfer coefficient U is equivalent to better cooling the solar module.

[0018] However, other factors should also be considered when effectively cooling solar modules, such as cost, the weight of the solar modules, and the long-term stability of the solar modules.

[0019] For example, with a temperature coefficient Tk of -0.35% / K (for a Cu(In,Ga)(S,Se)2-based solar module), improved cooling of the solar module increases efficiency by 7% by lowering the operating temperature by 20°C. Therefore, the material requirements and associated costs for cooling should not exceed the added value in terms of electrical output. Furthermore, the weight of the solar module needs to be considered. An increase in weight, for example, exceeding 20 kg, is problematic because solar module installation is typically done manually by installers, increasing not only labor costs but also the requirements for the mounting structure. Additionally, the long-term stability of the solar module needs to be considered. Solar modules typically operate at system voltages between 1000V and 1500V. As described in WO2015004244 A1, the combined effect of high voltage, high humidity, and high temperature can trigger potential degradation (PID effect), which reduces the electrical output of the solar module. Surprisingly, the already very high electrical insulation of the glass itself is insufficient to avoid the PID effect. As described in the aforementioned literature, the PID effect can be effectively suppressed when the mounting structure, such as the frame or back rail, is highly electrically insulated.

[0020] In the prior art, various methods exist for cooling solar modules. Methods for cooling solar modules are summarized in Olawole et al.'s "Innovative methods of cooling solar panel: A concise review," 2019, J. Phys.: Conf. Ser. 1299 012020. Solar modules can be cooled using either passive or active cooling methods. In active cooling methods, a liquid or gaseous cooling medium is used to cool the solar module, and this cooling medium is circulated by a device such as a pump or fan. In passive cooling methods, heat is passively transferred to the environment without the need for a device to circulate the cooling medium.

[0021] Numerous patent documents concerning cooling solar modules cover various methods for liquid-cooled solar modules. Additionally, the PV / T hybrid module, well-known to those skilled in the art, is also a viable option. In this approach, excess heat from the solar module (PV) is dissipated through a solar collector (T) and can be used for heating. However, the combination of photovoltaic and solar thermal energy is technically very complex because piping for the cooling medium must be provided. Furthermore, compromises must be made between thermal and electrical energy, and the generated thermal and electrical energy is often insufficient to meet the actual needs of the building.

[0022] Combining solar modules with thermoelectric devices is another approach. For example, GB 2384113 A describes a scheme for actively cooling solar modules or using temperature differences to generate additional electrical output. Furthermore, an innovative approach involves using phase change materials, but this has not yet been implemented industrially. Summary of the Invention

[0023] The purpose of this application is to achieve sufficient passive cooling for solar modules. Furthermore, it aims to enable solar modules to possess high long-term stability unaffected by external environmental factors and to have a light weight. Additionally, it aims to enable the simple and inexpensive manufacture of solar modules in industrial production.

[0024] The above and other objectives of this application are achieved by a solar module with a passive cooling structure according to the independent claim. Preferred embodiments of this application are defined in the dependent claims.

[0025] Embodiments of this application provide a solar module with a passive cooling structure. The solar module includes a front glass and a rear glass, which are fixedly connected to each other via at least one intermediate layer. A plurality of solar cells connected in series are disposed between the front and rear glass. The front and rear glass are each made of glass, particularly soda-lime glass. The front glass forms the front side of the solar module. The front side of the solar module represents the side of the solar module facing incident light in its installed position. The rear glass forms the rear side of the solar module. The rear side of the solar module represents the side of the solar module away from incident light in its installed position.

[0026] The solar cell can be any solar cell suitable for a glass / glass solar module, particularly a thin-film solar cell or a silicon wafer cell. A (thin-film) solar module with a composite panel structure is preferred. The (thin-film) solar module has a transparent cover plate made of glass and a rear substrate made of glass, the cover plate and the substrate being fixedly connected to each other by a thermoplastic or cross-linked polymer interlayer (e.g., PVB or EVA).

[0027] Thin-film solar modules can be configured based on a substrate, wherein a layer system for forming thin-film solar cells is applied to the light-incident surface of a rear substrate. In this case, the rear substrate serves as a carrier for the layer system. Similarly, thin-film solar modules can be configured based on a cover plate, wherein a layer system is applied to the surface of a front cover plate away from the light-incident side. In this case, the front cover plate serves as a carrier for the layer system.

[0028] The solar modules of this application are particularly glass / glass solar modules with thin-film solar cells based on a substrate configuration. Specifically, the semiconductor layer is based on a copper indium gallium sulfide selenide compound (Cu(In,Ga)(S,Se)2). The solar module is preferably frameless.

[0029] In embodiments of this application, a passive cooling structure is disposed on the surface of the rear glass away from the solar cell. The passive cooling structure includes one or more cooling elements, and is particularly composed of one or more cooling elements. The passive cooling structure is preferably attached to the rear glass by an adhesive layer. The passive cooling structure does not have any device for the movement of liquid or gaseous cooling media used to cool the solar module. Heat generated by the solar module is passively discharged to the external environment via convection through the passive cooling structure.

[0030] The passive cooling structure has a contact surface at which it makes thermal contact with the rear glass for heat transfer, wherein the contact surface covers at least 90% of the photovoltaic active surface of the solar module. The passive cooling structure is fixedly connected to the rear glass in direct thermal contact with the rear glass as much as possible.

[0031] One or more cooling bodies are each made of a material having a thermal conductivity to density ratio of at least 0.02 W·cm. 2 / (g·K), preferably at least 0.05W·cm 2 / (g·K). One or more cooling elements are portions of a passive cooling structure that ensure convective heat transfer to the environment. The area ratio of the surface of the passive cooling structure furthest from the rear glass to the contact surface is at least 3, preferably at least 5, and particularly preferably at least 7.

[0032] The technical solution of this application allows the heat generated by the solar module to be efficiently and passively transferred to the external environment via convection, thus effectively cooling the solar module during operation. Furthermore, the heat transfer coefficient of the solar module is preferably at least 20 W / (K·m²). 2 Specifically, the passive cooling structure is preferably configured such that the heat transfer coefficient of the contact surface is at least 20 W / (K·m). 2 ).

[0033] Furthermore, the surface density of the passive cooling structure is less than 0.6 g / cm³. 2 Preferably less than 0.5 g / cm³ 2 A particularly preferred concentration is less than 0.4 g / cm³. 2 The mass surface density is the mass of the passive cooling structure per unit contact area. This allows for a relatively small increase in the weight of the solar module due to the cooling structure, in a particularly advantageous manner.

[0034] Furthermore, the passive cooling structure is designed such that, or connected to the rear glass of the solar module, the resistivity surface product of the passive cooling structure is greater than 4 × 10⁻⁶. 11 ohm·cm2, preferably greater than 2×10 12 ohm·cm2, preferably greater than 1×10 13 Ohm·cm², the resistivity surface area is the product of the contact area between the passive cooling structure and the rear glass and the electrical contact resistance. This effectively suppresses potential-induced degradation (PID effect).

[0035] Therefore, the solar module according to this application can be efficiently and passively cooled by the passive cooling structure, significantly reducing power loss caused by temperature. Furthermore, the PID effect and associated power loss of the solar module can be avoided. In addition, the passive cooling structure adds only a relatively small amount to the weight of the solar module, allowing it to still be mounted using conventional mounting elements (e.g., frames, multiple back rails, multiple mounting brackets).

[0036] As mentioned earlier, a passive cooling structure may have only one cooling element or multiple (separate) cooling elements. The terms "contact surface," "mass surface density," and "resistivity surface product" refer to the entire passive cooling structure, not individual cooling elements.

[0037] The cooling of the solar module according to this application is based on a suitable cooling structure with low mass areal density and a highly electrically insulated connection to the solar module. The solar module is essentially cooled solely by free convection in an efficient manner. The advantage of passive cooling over active cooling described in the prior art is that the design and installation complexity of the passive cooling structure is significantly lower. Furthermore, in addition to weight reduction, the passive cooling structure also offers cost optimization advantages. The solar module with a passive cooling structure according to this application is compatible with all common application areas and installation types, such as open spaces, rooftop installations, or facade installations (as part of a ventilated facade). In particular, the solar module can be used in ventilated facades.

[0038] The passive cooling structure has a finely structured surface that is far from the rear glass and significantly larger than the contact surface parallel to the rear glass. Advantageously, the contact surface has a size approximately the same as the entire area of ​​the solar cell.

[0039] As the inventors discovered based on a precise analysis of potential thermal problems, heat transfer is not determined by heat conduction through the solar module layers, but by the heat transfer coefficient U.

[0040] For simplified construction of a combination of exterior and interior walls, the following applies:

[0041] 1 / U=R T =R SE +d / λ+R si

[0042] Among them, R SE and R si Let represent the heat transfer resistance of the exterior and interior walls, and d represent the thickness of the wall with a thermal conductivity of λ.

[0043] In glass-to-glass solar modules, the contribution of thermal conductivity, or heat transfer resistance, is primarily provided by the two glass panels. With a total thickness, for example, d = 4 mm and a thermal conductivity λ of 0.8 W / K·m, d / λ = 0.005 m. 2 • K / W. The contribution of heat transfer resistance is significantly higher: for flat glass composites, the value specified in DIN standard EN ISO 6946 is 0.04m. 2 K / W to 0.17m 2 ·K / W.

[0044] The main objective of this application is to improve the heat transfer coefficient (i.e., reduce thermal resistance) of glass-to-glass solar modules while simultaneously meeting practical requirements regarding cost, weight, and long-term stability. Heat transfer resistance is composed of contributions from convection and radiation. The emissivity of the outer surface plays a decisive role in the proportion of radiation. Glass already possesses a relatively high emissivity of approximately 0.84. However, the proportion of radiation is small at relevant temperatures (40-70°C). Therefore, the contribution from convection has greater potential for improvement.

[0045] According to document WO2015004244 A1 mentioned in the background art, the insulation resistance requirement for grounded metal bodies (e.g., rear brackets (back rails) or frames) used for assembly can be described as follows: if the bonding surface reaches 1m... 2If the adhesive used to attach the metal body to the rear of the solar module is 1 mm thick and covers 5% of the solar module surface, then the resistivity of the bonded connection to the glass surface must be at least 5000 GOhm·cm, which corresponds to a resistance of 1 GOhm at the mentioned dimensions. However, the technical teachings known from WO2015004244 A1 cannot be easily transferred to the problem of highly insulated connections in passive cooling structures. It is currently unclear what requirements must be placed on the larger metal surface attached to the solar module, nor is the issue of moisture (dew, condensation, and rainwater) discussed. Furthermore, the document provides no information on how to handle conductors that are not directly grounded on the rear of the module.

[0046] Moisture can reach the back of the solar module through condensation or directly through rainwater. Rainwater has an average conductivity of 50 μS / cm, or a resistivity of 20 kOhm·cm. This is eight orders of magnitude higher than the specific conductivity required by the adhesive. In the case of contamination, the specific conductivity can be nine orders of magnitude higher than that required by the adhesive. The inventors were able to deduce from various literature sources and their own research that, for example, typical morning dew has a water level of approximately 0.01 to 0.1 mm. Even at such low levels, this corresponds to a thin-layer resistance of 2 to 20 MOhm / square. Therefore, the resistance parallel to the glass surface is 1 to 10 MOhm. The contact resistance across the entire glass surface is 1 to 2 GOhm (100 to 1000 times) depending on temperature. Compared to the glass surface, the thin water layer is almost an equipotential surface and opens a second leakage path, about 20 times smaller than the water layer and on the same order of magnitude as the path to the adhesive surface and the glass surface beneath it. Undisclosed research by the inventors indicates that these leakage currents through the glass actually occur in air-conditioned rooms and open spaces under conditions of higher temperature and condensing humidity. At the same temperature, these leakage currents are even significantly larger than those through adhesives due to the large glass surface area.

[0047] At a fixed voltage (system voltage, e.g., 1000V), resistance corresponds to ion current or leakage current, and at a fixed time (e.g., the required lifespan of the solar module), it corresponds to a certain amount of charge, resulting in a certain degradation in power per unit area. For example, since solar modules are mounted to a grounded mounting system via brackets or back rails, any other conductive surface on the back of the solar module will also degrade over time via cross-lines above that conductive surface and water bridges between the mounting system and the conductive surface if the insulation resistance between the conductive surface and the back of the module is not high enough. Therefore, improved passive cooling devices for solar modules must also have sufficiently high resistance between the outer surface of the cooling body and the interior of the module. The resistivity of soda-lime glass is exponentially related to temperature. At room temperature, this resistivity is typically on the same order of magnitude (~10) as the adhesives used in typical applications. 13In most technical contexts, glass can also serve as a very good insulating material. However, this resistivity is insufficient to guarantee long-term stability because at an operating temperature of 60°C, the resistivity drops by almost two orders of magnitude (~10 ohms·cm). 11 Other materials used in photovoltaics, such as EVA, also exhibit similar strong temperature dependence and are therefore unsuitable for this application.

[0048] Regarding the electrical insulation of the passive cooling structure, the following are the essential factors for this application:

[0049] Given the fundamental mechanism of ion migration through glass, the total resistance must not decrease when the bonding surface is large. As the bonding surface increases, the total resistance decreases while the specific resistance remains constant, leading to a greater amount of degraded charge. Therefore, the required specific resistance must increase with the ratio of the contact surface area to the original back rail bonding surface area. For larger conductive surfaces, in the case of persistent grounding, for 1m... 2 The resistivity of the 5000 GOhm·cm adhesive required for the back rail problem of the module is no longer sufficient. Throughout its lifespan, the total charge flowing through or the leakage current flowing through each unit area of ​​the module should not increase. Therefore, a suitable metric is the resistivity-surface product given by R×A=ρ×d. Thus, for a size of 1m... 2 Furthermore, for a module with a resistance of 2 GOhm, the required resistor surface product is 2 GOhm × 10. 4 cm 2 =2×10 13 Ohm·cm 2 .

[0050] Passive cooling structures should be laterally spaced from grounded mounting elements. However, if the passive cooling structure covers as large an area of ​​the solar cell as possible (>90%, preferably >95%) to effectively and uniformly cool the solar cell, the distance between the passive cooling structure and the mounting element can be only a few millimeters to a few centimeters. At the previously considered moisture levels, this distance translates to a connection resistance of only 10 to 100 kOhms. Furthermore, if the passive cooling structure is not adequately insulated, even a much smaller amount of moisture can lead to significant leakage paths.

[0051] As described above, the distance between the passive cooling structure and the grounded mounting elements (back rail, mounting bracket, possible frame or facade support (hook and clip)) is only a few millimeters to 2 cm. Condensation, rainwater, dust, dirt, air pollution, etc., will occupy this distance. Since the specific conductivity of condensation, rainwater, dust, dirt, air pollution, etc. is 8 orders of magnitude higher than that of the adhesive, even a very small amount of condensation, rainwater, dust, dirt, air pollution, etc. is sufficient to place the passive cooling structure almost at ground potential.

[0052] In one embodiment of this application (referring to the first embodiment described below and in the detailed embodiments), in order to induce a larger leakage current through the passive cooling structure and the glass, a moisture film must be formed over the entire passive cooling structure. This is difficult to achieve; however, the solar module should exhibit low levels of performance degradation in all climate zones and under various environmental conditions.

[0053] In one embodiment of this application (referring to the second embodiment described below and in the detailed embodiments) with an insulating layer between the rear glass and the highly conductive passive cooling structure, the large-area passive cooling structure is almost grounded through contact bridges over a small insulating path. Without adequate insulation of the passive cooling structure, leakage current would occur across the entire glass surface. Compared to conventional solar modules with rear rails, the bridging distance in this case is very short, increasing the probability of such leakage current bridging.

[0054] The highly electrically insulated passive cooling structure required by this application is also advantageous: compared to glass / glass solar modules, the passive cooling structure can even be used to improve PID stability under critical climatic and / or environmental conditions, because the resistance of the passive cooling structure limits leakage current better than that of a free glass surface, even at higher temperatures.

[0055] For permanent grounding connections, such as those with a 500cm radius... 2 The back rail of the adhesive surface and for 1m 2 The resistance of the 2GOhm adhesive module has been shown to be sufficiently stable in air-conditioned room experiments and long-term outdoor area tests. The entire surface adhesive corresponds to 2×10⁻⁶. 13 Ohm·cm 2 The product of the resistivity surfaces. The probability of conductive connections occurring depends on actual climatic and environmental conditions. Therefore, the required insulation value is assumed to be 2%, 10%, or 50% of the operating time. This results in a resistivity surface product value of 4 × 10⁻⁶. 11 Ohm·cm 2 Preferably 2×10 12 Ohm·cm 2 And it is particularly preferred to be 1×10 13 Ohm·cm 2 A 1mm insulation layer thickness corresponds to 4×10 12 Ohm·cm, preferably 2×10 13 Ohm·cm and preferably 1×10 14 The resistivity is measured in Ohm·cm. Simulations show that, in the presence of moisture, a 1mm thick material with a resistivity of at least 1×10⁻⁶ can be used. 13 Adding an additional Ohm·cm layer to the entire surface reduces leakage current by almost an order of magnitude.

[0056] Suitable passive cooling structures require materials with high thermal conductivity, excellent electrical insulation, and low density. Table 1 shows the material properties of various known materials in order of increasing thermal conductivity: Table 1: Main Properties of Various Materials

[0057]

[0058] The desired properties, such as good thermal conductivity, low density, and high insulation resistance, exist only in a few materials. Metals have very good thermal conductivity, but they also have high density, and especially high electrical conductivity. Aluminum has good thermal conductivity and a relatively low specific gravity, therefore, it is widely used in coolants.

[0059] Ceramic materials, such as Al2O3, AlN, MgO, and BN, have broken the correlation between thermal conductivity and electrical thermal conductivity. Composite materials composed of polymers and various insulating fillers, such as BN, Al2O3, Si3N4, and SiO2, exhibit only low thermal conductivity but good insulation and very low density.

[0060] The solar module with the specific passive cooling structure of this application takes the above factors into consideration.

[0061] The passive cooling structure has a contact surface at which it makes thermal contact with the rear glass for heat conduction. The contact surface covers at least 90% of the photovoltaic active surface of the solar module.

[0062] The area ratio of the surface of the passive cooling structure away from the rear glass to the contact surface is at least 3, preferably at least 5, and particularly preferably greater than 7.

[0063] One or more cooling bodies are each made of a material having a thermal conductivity to density ratio of at least 0.02 W·cm. 2 / (g·K), preferably at least 0.05W·cm 2 / (g·K).

[0064] The surface density of the passive cooling structure is less than 0.6 g / cm³. 2 Preferably less than 0.5 g / cm³ 2 A particularly preferred concentration is less than 0.4 g / cm³. 2 The surface density is the mass of the passive cooling structure per unit contact surface.

[0065] To achieve the most uniform temperature distribution possible, the passive cooling structure should cover at least 90%, preferably 95%, and particularly preferably 100% of the entire area of ​​the solar cell. The passive cooling structure can also cover the entire rear side of the solar module, corresponding to 105% to 110% of the photovoltaic active surface of the solar module.

[0066] The surface density of the entire passive cooling structure should be less than 0.6 g / cm³. 2 Preferably less than 0.5 g / cm³ 2 More preferably less than 0.4 g / cm³ 2 .

[0067] The product of the contact area and the contact resistance between the passive cooling structure and the rear glass should be greater than 4 × 10⁻⁶. 11 ohm·cm 2 Preferably greater than 2×10 12 ohm·cm 2 More preferably greater than 1×10 13 ohm·cm 2 .

[0068] The passive cooling structure is a three-dimensional structure with an enlarged surface. The area ratio of the surface of the passive cooling structure furthest from the rear glass to the contact surface is at least 3, preferably 5, and particularly preferably greater than 7.

[0069] The distance between the passive cooling structure and each grounded mounting element (frame, back rail, mounting bracket) is 1 mm to 20 mm, preferably 2 mm to 20 mm.

[0070] The thermal transfer resistance between solids, i.e., between the glass and each cooling element, should be kept as low as possible through bubble-free, tight adhesion. In the case of plastics, the cooling elements can be attached to the rear glass without an additional interlayer. In the case of ceramic materials, the cooling elements are attached to the rear glass by means of a very thin adhesive layer. The thermal transfer resistance from the solar cell to each cooling element is determined by the heat conduction through the rear glass (for glass / glass modules). The sum of the thermal transfer resistances should be as low as possible, less than 0.01 m. 2 • K / W. For example, the heat transfer resistance of a 2mm thick float glass plate is 0.0025m. 2 • K / W. The thermal resistance of the adhesive layer should be less than 0.005m. 2 • K / W. There is also interfacial resistance between the glass and the cooling body, minimized through close contact.

[0071] The heat transfer coefficient of the entire solar module is preferably at least 20 W / (K·m). 2 ), more preferably 40W / (K·m 2 The optimal value is greater than 50 W / (K·m). 2 ).

[0072] According to a first embodiment of the solar module of this application, the passive cooling structure includes one or more cooling elements. No insulating layer is provided between the cooling elements and the rear glass. The contact surface for heat transfer is formed by one or more cooling elements. When the passive cooling structure includes multiple cooling elements, the contact surface of the passive cooling structure is formed by the individual contact surfaces of the multiple cooling elements. When the passive cooling structure includes a single cooling element, the contact surface of the passive cooling structure is formed by the single contact surface of that cooling element.

[0073] In a first embodiment of the solar module according to this application, each of the cooling bodies is made of a material having a density of at least 10. 11 The resistivity of ohm·m eliminates the need for a highly electrically insulating layer to electrically insulate the coolant relative to the back glass. The coolant is preferably bonded directly (without an intermediate layer) to the surface of the back glass furthest from the solar cell. In this way, the coolant itself can ensure a resistivity greater than 4 × 10⁻⁶. 11 ohm·cm 2 The resistivity surface area product is the product of the contact area and electrical contact resistance between the passive cooling structure and the rear glass, which provides a relatively simple design. Preferably, for this purpose, each of the cooling bodies is made of a highly electrically insulating ceramic material or a polymer with ceramic filler. The ceramic material is at least one of AlN, Al2O3, Si3N4, MgO, or BN. The polymer is selected from a material composed of polyetheretherketone (PEEK) or polyamide 66 (PA66) with BN, Al2O3, or SiO2.

[0074] The core idea of ​​the first embodiment of the solar module according to this application is to achieve the above requirements from a small set of suitable materials. Simulations show that the thermal resistance at low weight is not determined by a single value of thermal conductivity and density, but by the ratio of thermal conductivity to density. There are selected materials with sufficiently high thermal conductivity-to-density ratios and very high resistivity. These materials include certain ceramic materials such as AlN, Si3N4, and Al2O3. Furthermore, there are relatively new categories of thermally conductive, highly insulating plastics. These plastics are formed by adding ceramic fillers to a polymer matrix. One or more coolants should be composed of materials having a thermal conductivity-to-density ratio of at least 0.02 W·cm⁻¹. 2 / (g·K), preferably 0.05W·cm 2 / (g·K).

[0075] In a second embodiment of the solar module according to this application, the passive cooling structure includes one or more cooling elements. Each cooling element is attached, preferably bonded, to the surface of the rear glass away from the solar cell by means of a highly electrically insulating layer made of a material having a density of at least 10. 11 The resistivity is ohm·m. Therefore, the cooling elements are in thermal contact with the rear glass via highly electrically insulating layers. Each individual contact surface of the cooling element is thus connected to the rear glass via an insulating layer.

[0076] The insulating layer is preferably designed in a similar manner to the contact surface of the passive cooling structure. If the passive cooling structure comprises only one cooling element, the insulating layer preferably has the same size as the contact surface of that cooling element. If the passive cooling structure comprises multiple cooling elements, the insulating layer is provided only on the contact surfaces of the multiple cooling elements, i.e., no insulating layer is provided at locations where there is no contact surface between the passive cooling structure and the rear glass. Alternatively, the insulating layer may also be provided at locations where there is no contact surface between the passive cooling structure and the rear glass.

[0077] The PID effect can be effectively prevented by using an insulating layer. In this case, the cooling body can be made of inexpensive, readily available, and easy-to-process materials that do not have high electrical insulation properties.

[0078] The core idea of ​​the second embodiment of the solar module according to this application is to meet the aforementioned requirements by applying different layers of different materials to the surface of the rear glass of the solar module away from the solar cells. A passive cooling structure is connected to the rear glass of the solar module via a highly electrically insulating layer. For example, the insulating layer can be a silicone adhesive with high insulation resistance and sufficient thickness. Advantageously, the insulating layer can also be a thicker film composed of silicone resin or ionomer. The resistance of the highly insulating layer should not decrease by more than two times from room temperature to 85°C. Alternatively, the highly insulating layer can be a thin layer composed of a ceramic material with good thermal conductivity, such as AlN, Al2O3, BN, or Si3N4. This thin layer is then connected to the rear glass by, for example, a very thin adhesive layer.

[0079] Therefore, the material constituting the insulating layer is advantageously selected from highly insulating ceramic materials or polymers with ceramic fillers. The ceramic material is at least one of AlN, Al2O3, Si3N4, MgO, or BN, and the polymer is selected from materials composed of polyetheretherketone (PEEK) or polyamide 66 (PA66) with BN, Al2O3, or SiO2. Alternatively, the insulating layer can also be made of silicone resin, particularly in the form of silicone resin adhesives or silicone resin films. The coolant can be individually bonded to the rear glass via silicone resin films. If the highly electrically insulating layer is not made of adhesive, the coolant is individually bonded to the highly electrically insulating layer via adhesive layers, which in turn are bonded to the rear glass. Typically, the adhesive layers have much lower resistance, making the resistance of the highly electrically insulating layer important.

[0080] The cooling body is advantageously constructed from metallic materials and / or graphite, particularly aluminum, copper, and magnesium alloys. These materials are inexpensive, readily available, and can be easily processed using conventional methods. In the second embodiment, the cooling body is also constructed from a material having a thermal conductivity to density ratio of at least 0.02 W·cm⁻¹. 2 / (g·K), preferably 0.05W·cm 2 / (g·K).

[0081] The passive cooling structure comprises one or more (three-dimensional) cooling elements. Each of the cooling elements has a base surface (i.e., a single contact surface) on which the passive cooling structure makes thermal contact with the rear glass and enables the solar module to be cooled by heat conduction.

[0082] The surface of the passive cooling structure away from the rear glass is enlarged relative to the contact surface (i.e., the sum of the contact surfaces of the multiple cooling elements), and the size of this surface is designed such that the area ratio of the passive cooling structure's surface to the contact surface is at least 3. For example, an area ratio of 3 means that the surface of the passive cooling structure away from the rear glass is three times the size of the contact surface. This allows for effective cooling of the solar module while maintaining sufficient mechanical stability in the passive cooling structure. Preferably, the area ratio of the passive cooling structure's surface away from the rear glass to the contact surface is at least 5, and particularly preferably at least 7.

[0083] To expand the surface area, the cooling bodies advantageously have flat bases and portions projecting from the bases, such as ribs or pins. The ribs or pins have elongated shapes, having a long dimension (length) and two much shorter dimensions (height and thickness) within the plane of the solar module. The pins have elongated shapes, with the longer dimension perpendicular to the plane of the solar module (height) and the two smaller dimensions parallel to the plane of the solar module. Heat conduction between the rear glass and each of the cooling bodies occurs on the flat base. The flat base of each of the cooling bodies forms the base surface (i.e., a single contact surface) of the cooling body for heat conduction.

[0084] The adhesive layer used to attach the coolant to the rear glass or the adhesive layer used to attach a highly electrically insulating layer to the coolant or rear glass is not a decisive factor in heat conduction and can usually be ignored.

[0085] In principle, the protrusion can have any shape, preferably a rib or a pin. A rib with a long dimension within the plane of the solar module allows for optimal cooling of airflow in one direction. The spacing between two ribs provides a channel-like structure for the flowing air. Pins have slightly lower cooling efficiency but allow for bidirectional cooling. This is important if the same module type is installed vertically on a building facade with the module axis in the longitudinal direction parallel not only to (longitudinal format) but also perpendicular to (lateral format) the vertical axis of the building. Bidirectional cooling can also result in a more uniform temperature distribution. Modifying the geometry to a gradually tapering longitudinal section or other cross-section is also feasible. In the case of cooling ribs, the most important structural parameters determining surface enlargement and mass areal density are the spacing between two adjacent ribs, the thickness of the cooling rib, the height of the cooling rib, and the thickness of the base. In the case of cooling pins, the most important structural parameters, in addition to the above, include the spacing and thickness in the second spatial dimension.

[0086] Heat transfer via convection depends largely on the thickness of the air boundary layer formed at the surface of the coolant. The spacing between the pins or ribs should be at least 0.5 mm, preferably at least 1 mm, and particularly preferably at least 2 mm. The base must conduct heat to the cooling ribs or pins. For this purpose, a relatively small thickness is sufficient. Furthermore, depending on the design, the base has a mechanical function of securing the cooling ribs or pins together. However, from the perspective of mass reduction, the base is inefficient.

[0087] Advantageously, the protrusions, such as cooling ribs or cooling pins, have a thickness of less than 2 mm, preferably less than 1 mm, preferably less than 0.5 mm, preferably less than 0.2 mm, and particularly preferably less than 0.08 mm, and the thickness of the base of each cooling element is less than 0.2 mm, preferably less than 0.1 mm, and particularly preferably less than 0.05 mm. These dimensional requirements advantageously ensure effective cooling of the solar module while maintaining a low surface mass density.

[0088] In the first embodiment of the solar module according to this application, the spacing between the cooling pins or cooling ribs should be at least 0.5 mm, preferably at least 1 mm, and particularly preferably at least 2 mm. The thickness of each of the cooling ribs or cooling pins should be less than 2 mm, preferably less than 1 mm, and particularly preferably less than 0.5 mm. The aspect ratio of the height to the thickness of the cooling ribs or cooling pins should be greater than 20, preferably greater than 40. The thickness of the base is advantageously greater than that in the second embodiment of the solar module according to this application because the base is used for electrical insulation and must meet high requirements regarding the resistivity surface product. The thickness of the base in the first embodiment should be less than 2 mm, preferably less than 1 mm, and particularly preferably less than 0.7 mm.

[0089] Multiple cooling structures were simulated. For this purpose, the one-dimensional model of the cooling ribs was extended to include a periodic arrangement of these ribs or pins on the substrate. The specified dimensions depend on various assumptions, particularly the assumed heat transfer coefficient between the cooling rib surface and the air. This heat transfer coefficient depends on the surface properties and local flow conditions. For example, the average heat transfer coefficient was 15 W / (m²). 2 ·K). This example is only for illustrating a structure that is feasible in principle. For calculations, assume 1m 2 The solar module has a power of 50W / (m²) 2 The overall heat transfer coefficient (·K) is less than that per 1m 2 The total mass of the coolant is 4 kg, meaning its surface density is 0.4 g / cm³. 2 For bonding and adhesion to the glass, a thermal resistance of 0.0001 K / W is assumed, and for the rear glass, a thermal conductivity resistance of 0.0025 K / W is assumed. The example described can also be applied to other module sizes. Pins and other geometries are also feasible. Table 2 shows monolithic coolers with ribs made of various thermally conductive, highly insulating materials:

[0090] Table 2

[0091]

[0092] Similar considerations also apply to the second embodiment of the solar module according to this application. Preferred materials for at least one cooling element are metals with an optimal ratio of thermal conductivity to specific gravity and acceptable raw material costs, such as aluminum, copper, and magnesium alloys. Graphite is also suitable for the cooling element. The thickness of each of the cooling ribs or cooling pins should be less than 0.5 mm, preferably less than 0.2 mm, and particularly preferably less than 0.08 mm. The aspect ratio of the height to the thickness of the cooling ribs or cooling pins is greater than 10, preferably greater than 20 and less than 200, and particularly preferably greater than 20 and less than 100, to provide necessary mechanical stability. In the second embodiment, the thickness of the base of the passive cooling structure should be less than 1 mm, preferably less than 0.5 mm, and particularly preferably less than 0.2 mm.

[0093] Simulations were performed on various passive cooling structures. The examples are for illustrative purposes only, highlighting structures that are feasible in principle. For calculation purposes, a 1m... 2 The solar module has a power of 50W / (m²) 2 The overall heat transfer coefficient (K) and per 1m 2 The total mass of the cooling element is 3 kg (i.e., its surface density is 0.3 g / cm³). 2 The target value is [value missing]. Assume the thermal conductivity resistance of the insulation layer is 0.005 K / W, and the thermal conductivity resistance of the rear glass is 0.0025 K / W. To achieve the necessary insulation, a specific resistivity of 1 × 10 [units missing] is used. 13 ohm·cm, thickness 1mm, density approximately 1g / cm³ 3 An adhesive (e.g., silicone) is used as an insulating layer. This increases the total mass per unit area of ​​the passive cooling structure by 0.1 g / cm³. 2 It is 0.4 g / m 2 This example can also be transferred to other module sizes, as the absorbed heat is directly proportional to the module size. Those skilled in the art can convert the parameters based on the product of mass surface density and resistivity. Tables 3-5 show some examples of coolants made of various materials.

[0094] Table 3: Examples of ribbed cooling bodies made of aluminum

[0095] Material Al Al Al Al Thickness of the base of the cooling element (cm) 0.03 0.03 0.02 0.01 Thickness of cooling ribs (cm) 0.03 0.03 0.04 0.05 Spacing of cooling ribs (cm) 0.6 1.1 0.4 0.7 Height of cooling ribs (cm) 1.5 2.5 0.9 1.5 Number of cooling ribs 103 58 148 87 Thermal resistance of the cooling element (K / W) 0.0116 0.0129 0.0128 0.0132 Thermal resistance of solar module (K / W) 0.0189 0.0202 0.0201 0.0205 <![CDATA[Heat transfer coefficient of solar module W / (m 2 ·K)]]> 53 50 50 49 The ratio of the surface area to the contact area of ​​the cooling structure 5.8 5.4 5.1 5.0 Aspect ratio of height to thickness 50 83 23 30

[0096] Table 4: Examples of ribbed cooling bodies made of other metals

[0097]

[0098] Table 5: Examples of cooling bodies with pins

[0099]

[0100] The thickness, spacing, and height of the cooling ribs or pins—that is, the total volume of the cooling ribs or pins—are limited by the upper mass limit. Due to convection conditions relative to the distance between the cooling elements, they cannot be arranged as densely as desired. A tightly meshed grid acts as a thermal insulator because air cannot flow well within it. On one hand, the base distributes heat from the gaps to the cooling ribs or pins; on the other hand, the base must ensure the mechanical fixation of the structure. The thickness of the base is crucial because the base itself does not contribute to cooling but does contribute to the overall mass.

[0101] A large surface area is created in a passive cooling structure using thin, high-aspect-ratio cooling ribs or pins. The extent of this surface area largely determines the cooling effect. However, the cross-sectional dimensions should not be too small; otherwise, heat distribution will no longer be possible across the entire surface, up to the top of the cooling ribs or pins. In the case of cooling pins, the lower limit of the thermal conductivity-to-density ratio is high. For example, cooling ribs or pins made of steel and titanium cannot be achieved with a given mass surface density and desired heat transfer coefficient without violating the distance between the ribs or pins. The optimal solution is to use materials with the highest thermal conductivity-to-density ratio, such as aluminum, magnesium alloys, graphite, or even silicon. Silicon is not considered due to cost. Cooling ribs or pins made of heavy elements, such as copper or zinc, must have a very high aspect ratio because the ribs or pins must be very thin due to the large weight of these heavy elements.

[0102] Passive cooling structures may include one or more cooling elements. The cooling elements are individually formed and spatially separated from each other. Multiple cooling elements are advantageously arranged such that the distance between two cooling elements is at least 0.1 mm, preferably 0.1 mm to 1 mm. Due to the different temperature coefficients of the glass and cooling element materials, multiple cooling elements can be used to compensate for stress. Multiple cooling elements also offer advantages in production and bonding. Therefore, the cooling elements do not need to be manufactured as large, continuous blocks.

[0103] In the second embodiment of the solar module according to this application, the passive cooling structure can be cut multiple times in at least one dimension in the lateral direction down to the insulation layer or down to the rear glass. The width of the groove formed by cutting the passive cooling structure should be in the range of 0.1 to 1 mm. This reduces the requirements for the insulation layer because the entire passive cooling structure is no longer a continuous, low-resistance conductor. For example, if the cooling body is connected to the mounting element at a lower resistance location via a local contact bridge, the connection no longer needs to exist across the entire module surface.

[0104] The solar module is preferably a frameless solar module and can be connected to the mounting structure, for example, via a bracket (back rail) disposed at the rear glass. Typically, the solar module may have one or more mounting elements (e.g., a rear rail, module bracket, or frame). Preferably, the spacing between the passive cooling structure and each mounting element for mounting the solar module is 1 mm to 20 mm, preferably 2 mm to 20 mm, which achieves good electrical insulation. The back rail is preferably used as a mounting element.

[0105] Embodiments of this application also provide a method for manufacturing a solar module, the method comprising the steps of: providing a front glass and a rear glass, the front glass and the rear glass being fixedly connected to each other by at least one intermediate layer, wherein a plurality of solar cells connected in series are disposed between the front glass and the rear glass; and attaching a passive cooling structure having one or more cooling elements to a surface of the rear glass remote from the plurality of solar cells. This method is applicable to any solar module according to embodiments of this application.

[0106] The method advantageously includes attaching at least one mounting element for mounting the solar module to the solar module such that the distance between each cooling body adjacent to the mounting element and the mounting element is 1 mm to 20 mm, preferably 2 mm to 20 mm.

[0107] Embodiments of this application also provide a use of solar modules as part of a building's ventilated facade. If multiple solar modules are located within a few centimeters of the wall, the airflow from the solar modules is additive. Therefore, even in conditions of very low external wind intensity, cooling via forced convection can be achieved instead of purely natural convection (windless freestanding solar modules): heat emitted by each cooling structure rises upwards, and cool air enters from below. The airflow then cools the solar modules via the individual cooling structures. For this purpose, sufficient air ducts must be provided at the lower and upper edges of the facade.

[0108] Through the above embodiments, the solar module with a passive cooling structure according to this application can advantageously achieve efficient cooling of the solar module, thereby significantly reducing power loss caused by temperature. Furthermore, the PID effect and associated power loss of the solar module can be avoided. In addition, the additional cooling structure causes only a relatively small increase in the weight of the solar module, allowing the solar module to be mounted using conventional mounting elements.

[0109] Various embodiments of this application can be implemented individually or in any combination. In particular, without departing from the scope of this application, the features mentioned above and explained below can be used not only in the illustrated combinations, but also in other combinations or individually. Attached Figure Description

[0110] The present application will now be explained in more detail with reference to exemplary embodiments and accompanying drawings, which are shown simply and not to scale:

[0111] Figure 1 This is a cross-sectional view of a solar module with a passive cooling structure according to the first embodiment of this application;

[0112] Figure 2 This is a cross-sectional view of a solar module with a passive cooling structure according to the second embodiment of this application;

[0113] Figure 3 This is a cross-sectional view of a solar module with a passive cooling structure according to a third embodiment of this application;

[0114] Figure 4 for Figure 3 Rear view of the solar module shown;

[0115] Figure 5 This is a cross-sectional view of the cooling ribs or cooling pins of the passive cooling structure according to an embodiment of this application;

[0116] Figure 6 This is a cross-sectional view of the cooling ribs or cooling pins of the passive cooling structure according to an embodiment of this application;

[0117] Figure 7 This is a flowchart of a method for manufacturing a solar module with a passive cooling structure according to an embodiment of this application. Detailed Implementation

[0118] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure are within the scope of protection of this disclosure.

[0119] Figure 1 A cross-sectional view of a solar module with a passive cooling structure according to a first embodiment of this application is shown. The solar module according to this application, with regard to the above-described general features, and particularly the features described in conjunction with the first embodiment, can be used in... Figure 1 Provided by China.

[0120] exist Figure 1In this solar module 1, a front glass 2 and a rear glass 3 are fixedly connected to each other via at least one intermediate layer 4, such as a thermoplastic intermediate layer, preferably by lamination. A series-connected solar cell 5 is disposed between the front glass 2 and the rear glass 3 and is used to convert sunlight into electrical energy. The front glass 2 forms the front side of the solar module 1, i.e., the light-entry side, from which sunlight enters the solar cells. The rear glass 3 forms the rear side of the solar module 1, away from the light-entry side.

[0121] A passive cooling structure 7 is provided on the surface of the rear glass 3 away from the solar cell 5. The passive cooling structure 7 has a contact surface 13, which is in thermal contact with the rear glass 3 for heat conduction. The area ratio of the surface of the passive cooling structure 7 away from the rear glass 3 to the area of ​​the contact surface 13 is at least 3, preferably at least 5, and particularly preferably greater than 7.

[0122] The passive cooling structure 7 may include one or more cooling elements 8. Figure 1 The cooled structure 7 consists of a cooling body 8, which is fixedly connected to the rear glass 3 in a manner that allows for thermal contact with the rear glass 3. For example, the cooling body 8 is adhered to the surface of the rear glass 3 away from the solar cell 5 using an adhesive. Figure 1 (Not shown). The cooling body 8 includes a base 9 and a plurality of protrusions 10 projecting from the base 9, such as cooling ribs or cooling pins. For example, cooling ribs may be arranged parallel to each other on the base 9 and extend along the entire length of the base 9. For example, cooling pins may be evenly arranged across the entire base 9. The cooling body 8 is monolithic (i.e., one-piece or integral).

[0123] The base 9 of the cooling body 8 is a continuous, uninterrupted region of the cooling body 8, which is, for example, rectangular in shape. Cooling ribs or cooling pins protrude from the base 9 in a direction away from the rear glass 3. The base 9 has a continuous (e.g., rectangular) base surface 11 for heat conduction between the rear glass 3 and the cooling body 8. The cooling body 8 is directly bonded to the surface of the rear glass 3 away from the solar cell via an adhesive layer (not shown). The base surface 11 forms a contact surface 13 of the passive cooling structure 7 for heat conduction between the rear glass 3 and the cooling body 8.

[0124] The base surface 11 of the base 9 has a size that is substantially the same as the entire area of ​​the solar cell 5. That is, the base surface 11 has a size that is substantially the same as or the same as the photovoltaic active surface of the solar module 1.

[0125] The passive cooling structure 7 is a three-dimensional cooling structure with an enlarged surface through cooling ribs or cooling pins. An enlarged surface means that the area of ​​the surface of the passive cooling structure 7 furthest from the rear glass 3 is greater than the area of ​​the base surface 11 or contact surface 13 of the base 9. The area ratio of the surface of the passive cooling structure 7 furthest from the rear glass 3 to the base surface 11 is at least 3, preferably at least 5, and particularly preferably greater than 7.

[0126] The cooling body 8 may be made of a thermal conductivity to density ratio of at least 0.02 W·cm⁻¹. 2 / (g·K), preferably at least 0.05W·cm 2 The material composition is / (g·K) for good heat transfer.

[0127] The coolant 8 can be made of a lightweight, highly electrically insulating, and simultaneously highly thermally conductive material. For example, the material is selected from highly insulating ceramic materials or highly insulating and thermally conductive polymers. The ceramic material is, for example, at least one of AlN, Al2O3, Si3N4, MgO, or BN. The polymer is, for example, a material composed of polyetheretherketone (PEEK) or polyamide 66 (PA66) and various fillers (e.g., BN, Al2O3, or SiO2). Importantly, the material of the coolant 8 should have a resistivity of at least 10 Ω·cm. 11 An electrical insulator of ohm·m.

[0128] The cooling body 8 is part of the passive cooling structure 7, which ensures convective heat transfer to the environment through an enlarged surface.

[0129] The solar module 1 may also include one or more mounting elements 6 (e.g., rear rails or back rails) located at the outer edge of the rear glass 3. The mounting elements 6 are fixedly connected to the rear glass 3. The mounting elements 6 are used for mechanical fixation of the solar module 1. A passive cooling structure 7 is spaced apart from the mounting elements. Specifically, a cooling body 8 is spatially spaced from the mounting elements 6. The distance between the cooling body 8 and the mounting elements 6 is 1 mm to 20 mm, preferably 2 mm to 20 mm.

[0130] Figure 2 The image shows a solar module 1 with a passive cooling structure according to a second embodiment of this application. To avoid unnecessary repetition, only the following description is provided. Figure 1 The differences shown are in the solar modules.

[0131] exist Figure 2 In the solar module 1, the passive cooling structure 7 includes a cooling body 8. Furthermore, a highly electrically insulating layer 12 is disposed between the cooling body 8 and the rear glass 3. The cooling body 8 is connected to the rear glass 3 via the insulating layer 12. The insulating layer 12 extends entirely over the contact surface 13 or base surface 11 of the base 9.

[0132] Insulating layer 12 is made of a material with a resistivity of at least 10 Ω·cm. 11 A highly electrically insulating layer made of a material with an ohm·m thickness. The insulating layer 12 has a thickness of 1 mm or less. Since the thickness of the insulating layer 12 is 1 mm or less, the requirement for the thermal conductivity of the insulating layer 12 can be less stringent. The insulating layer 12 electrically isolates the cooling body 8 from the rear glass 3, making the cooling body 8 highly electrically insulated relative to the rear glass 3.

[0133] The insulating layer 12 can be composed of any one of ceramic materials, polymers with ceramic fillers, and silicone resins. For example, the ceramic material can be at least one of AlN, Al2O3, Si3N4, MgO, and BN; the polymer can be a material composed of polyether ether ketone (PEEK) or polyamide 66 (PA66) with BN, Al2O3, and SiO2; and the silicone resin can be a silicone adhesive or a silicone film.

[0134] For example, insulating layer 12 is made of a silicone resin adhesive with high insulation resistance and sufficient thickness. A thicker film made of silicone resin or ionomer can also be used as insulating layer 12. Insulating layer 12 made of silicone resin adhesive is self-adhesive, therefore no additional adhesive layer is required. If insulating layer 12 is not self-adhesive, then corresponding adhesive layers must be provided on both sides of insulating layer 12. The electrical and thermal transfer properties of the adhesive layers are secondary in the context of this application and need not be considered. Insulating layer 12 can also be made of a ceramic material that is highly thermally conductive and simultaneously highly electrically insulating, such as AlN, Al2O3, BN, or Si3N4. The thickness of insulating layer 12 is, for example, 1 mm.

[0135] In this embodiment, the ratio of thermal conductivity to density is at least 0.02 W·cm. 2 / (g·K), preferably at least 0.05W·cm 2 All materials with a density of / (g·K) are suitable as materials for the coolant 8. These materials do not need to be highly electrically insulating. Therefore, in addition to the materials mentioned above for the coolant 8, these materials can also include metals such as aluminum, copper, or magnesium alloys. Furthermore, the coolant 8 can be made of graphite. Such materials are inexpensive, readily available, and easy to process.

[0136] Figure 3 A cross-sectional view of a solar module 1 with a passive cooling structure according to a third embodiment of this application is shown. To avoid unnecessary repetition, only descriptions of... Figure 2 The differences shown are in the solar modules.

[0137] and Figure 2 The illustrated embodiment differs in that the passive cooling structure 7 includes multiple cooling elements 8. For example, in... Figure 3The passive cooling structure 7 includes four cooling elements 8. Furthermore, the passive cooling structure 7 may include more or fewer cooling elements 8. The number of cooling elements and the size of each cooling element 8 can be arbitrarily selected according to actual needs. The multiple cooling elements 8 are spaced apart from each other. For example, the distance between directly adjacent cooling elements 8 is 0.1 mm to 1 mm. Dividing the passive cooling structure 7 into multiple cooling elements 8 can facilitate the manufacturing process. The contact surface 13 of the passive cooling structure 7 is composed of the individual contact surfaces 14 or base surfaces 11 of the multiple cooling elements 8. It is also feasible to design the insulating layer 12 as a continuous layer without interruption between the cooling elements 8, such as... Figure 3 The two cooling bodies 8 on the left side are shown. There is an insulating layer 12 between the adjacent cooling bodies 8.

[0138] In addition, such as Figure 3 As shown, the mounting element 6 (e.g., rear rail or back rail) is spaced apart from the passive cooling structure 7. Specifically, the distance between the nearest cooling element 8 to one of the plurality of cooling bodies 8 and that mounting element is 1 mm to 20 mm, preferably 2 mm to 20 mm.

[0139] In this embodiment, the multiple cooling bodies 8 can be arranged in a grid. Figure 4 An example of this mesh-like structure consisting of multiple cooling elements 8 is shown on the rear glass 3. Mounting element 6 is located in... Figure 4 Not shown in the image.

[0140] Figure 5 This is a cross-sectional view of the cooling ribs or cooling pins of a passive cooling structure according to an embodiment of this application. Figure 5 The image shows a separate cooling element 8. As described above, the cooling element 8 has a base 9 and protrusions 10, such as cooling ribs or cooling pins. Figure 6 A cross-sectional view of a passive cooling structure or cooling pin according to an embodiment of this application is shown. Figure 6 The left side shows a single cooling element with multiple cooling ribs. Figure 6 The right side shows a single cooling element with multiple cooling pins.

[0141] If the protrusion 10 is a cooling rib, the cooling ribs are arranged parallel to each other on the base 9, such as Figure 6As shown on the left. Cooling ribs protrude from the base 9 in a direction away from and substantially perpendicular to the rear glass 3, and each has a height h and a thickness dk. The distance between adjacent cooling ribs is s. The thickness of the base 9 is denoted by db. If the passive cooling structure 7 has a pin structure with cooling pins, that is, in addition to the parameters mentioned above, it also has a distance s' and a thickness dk' in a second spatial dimension. In the case of (symmetrical) arrangement of cooling pins, the distance s' corresponds to the distance s and the thickness dk' corresponds to the thickness dk. However, this application is not limited to the symmetrical arrangement of cooling pins. Generally, the cooling body 8 is arranged symmetrically, which is advantageous in terms of low cost and simple manufacturing.

[0142] Typically, the distance s or s' between directly adjacent cooling ribs or cooling pins is at least 0.5 mm, preferably at least 1 mm, and particularly preferably at least 2 mm.

[0143] exist Figure 1 In the illustrated embodiment, the cooling ribs or cooling pins each have a thickness dk of less than 2 mm, preferably less than 1 mm, and particularly preferably less than 0.5 mm. The height h of each cooling rib or cooling pin is determined by the ratio of height h to thickness dk (which is called the aspect ratio). The aspect ratio is greater than 20 and less than 200, preferably greater than 40 and less than 100. For example, for a cooling rib or cooling pin with a thickness dk of 0.5 mm and an aspect ratio of 20, the height h of the cooling rib or cooling pin is 10 mm.

[0144] When the cooling body 8 is connected to the rear glass 3 via the insulating layer 12, such as Figure 2 As shown, the cooling ribs or cooling pins can, for example, have a thickness dk of less than 0.5 mm, preferably less than 0.2 mm, and particularly preferably less than 0.08 mm. For example, the thickness db of the base 9 can be less than 0.2 mm, preferably less than 0.1 mm, and particularly preferably less than 0.05 mm. For example, the aspect ratio is greater than 10 and less than 200, preferably greater than 20 and less than 200, and particularly preferably greater than 20 and less than 100. For example, for a cooling rib or cooling pin with a thickness dk of 0.2 mm and an aspect ratio of 20, the height h of the cooling rib or cooling pin is 4 mm.

[0145] Figure 7 This is a flowchart of a method for manufacturing a solar module 1 having a passive cooling structure 7 according to an embodiment. The method includes steps S1 and S2.

[0146] At S1, a front glass 2 and a rear glass 3 are provided, wherein the front glass 2 and the rear glass 3 are fixedly connected to each other by at least one intermediate layer 4, and a plurality of solar cells 5 connected in series are disposed between the front glass 2 and the rear glass 3.

[0147] At point S2, a passive cooling structure 7 having one or more cooling bodies 8 is bonded to the surface of the rear glass away from the solar cell 5.

[0148] The passive cooling structure 7 has a contact surface 13 at which it makes thermal contact with the rear glass 3 for heat conduction. The contact surface 13 covers at least 90% of the photovoltaic active surface of the solar module 1.

[0149] The area ratio of the surface of the cooling structure 7 away from the rear glass 3 to the contact surface 13 is at least 3, preferably at least 5, and particularly preferably greater than 7.

[0150] Each of one or more cooling bodies 8 is made of a material having a thermal conductivity to density ratio of at least 0.02 W·cm⁻¹. 2 / (g·K), preferably at least 0.05W·cm 2 / (g·K).

[0151] The surface density of the passive cooling structure 7 is less than 0.6 g / cm³. 2 Preferably less than 0.5 g / cm³ 2 A particularly preferred concentration is less than 0.4 g / cm³. 2 The mass surface density is the mass of the passive cooling structure 7 per unit contact surface.

[0152] The resistivity product of the passive cooling structure 7, i.e., the product of the contact area between the passive cooling structure 7 and the rear glass 3 and the electrical contact resistance, is greater than 4 × 10⁻⁶. 11 ohm·cm 2 Preferably greater than 2×10 12 ohm·cm 2 A preferred size is greater than 1×10. 13 Ohm·cm 2 .

[0153] Through the above embodiments, the solar module with a passive cooling structure according to this application can advantageously achieve efficient cooling of the solar module, thereby significantly reducing power loss caused by temperature. Furthermore, the PID effect and related power loss of the solar module can be avoided. In addition, the additional cooling structure causes only a relatively small increase in the weight of the solar module, allowing the solar module to be mounted using conventional mounting elements.

[0154] List of reference numerals

[0155] 1 Solar Module

[0156] 2. Front side glass

[0157] 3. Rear side glass

[0158] 4. Intermediate layer

[0159] 5. Solar cells

[0160] 6 Mounting Components

[0161] 7 Cooling Structure

[0162] 8 cooling body

[0163] 9. Base

[0164] 10. Protrusions (cooling ribs or cooling pins)

[0165] 11 (Single) Base Surface

[0166] 12 Insulation layer

[0167] 13 Contact surfaces

[0168] 14 Single contact surfaces

Claims

1. A solar module (1) comprising a front glass (2) and a rear glass (3), the front glass and the rear glass being fixedly connected to each other by at least one intermediate layer (4), wherein a plurality of solar cells (5) connected in series are disposed between the front glass (2) and the rear glass (3), and a passive cooling structure (7) having one or more cooling bodies (8) is disposed on the surface of the rear glass (3) away from the plurality of solar cells (5), wherein: The passive cooling structure (7) has a contact surface (13) at which it makes thermal contact with the rear glass (3) for heat conduction, wherein the contact surface (13) covers at least 90% of the photovoltaic active surface of the solar module (1); The area ratio of the surface of the passive cooling structure (7) facing away from the rear glass (3) to the contact surface (13) is at least 3; Each of the one or more cooling bodies is made of a material having a thermal conductivity to density ratio of at least 0.02 W•cm² / (g•K); The surface density of the passive cooling structure (7) is less than 0.6 g / cm³. 2 The mass surface density is the mass of the passive cooling structure (7) per unit contact area; The resistivity surface product of the passive cooling structure (7) is greater than 4 × 10⁻⁶. 11 ohm•cm², the resistivity surface product is the product of the contact area between the passive cooling structure (7) and the rear glass (3) and the electrical contact resistance.

2. The solar module (1) according to claim 1, wherein, The area ratio of the surface of the passive cooling structure (7) facing away from the rear glass (3) to the contact surface (13) is at least 5.

3. The solar module (1) according to claim 1, wherein, The area ratio of the surface of the passive cooling structure (7) facing away from the rear glass (3) to the contact surface (13) is greater than 7.

4. The solar module (1) according to claim 1, wherein, Each of the one or more cooling bodies is made of a material having a thermal conductivity to density ratio of at least 0.05 W•cm² / (g•K).

5. The solar module (1) according to claim 1, wherein, The surface density of the passive cooling structure (7) is less than 0.5 g / cm³. 2 .

6. The solar module (1) according to claim 1, wherein, The surface density of the passive cooling structure (7) is less than 0.4 g / cm³. 2 .

7. The solar module (1) according to claim 1, wherein, The resistivity product of the passive cooling structure (7) is greater than 2 × 10⁻⁶. 12 ohm•cm².

8. The solar module (1) according to claim 1, wherein, The resistivity product of the passive cooling structure (7) is greater than 1×10⁻⁶. 13 Ohm•cm².

9. The solar module (1) according to claim 1, wherein each of the one or more cooling bodies (8) comprises having at least 10 11 Materials with a resistivity of ohm•m.

10. The solar module (1) according to claim 9, wherein, The material is selected from ceramic materials or polymers with ceramic fillers, wherein the ceramic material is at least one of AlN, Al2O3, Si3N4, MgO and BN, and the polymer is selected from materials composed of polyether ether ketone (PEEK) or polyamide 66 (PA66) and BN, Al2O3 or SiO2.

11. The solar module (1) according to claim 1 further comprises a highly electrically insulating layer (12) having a resistivity of at least 10 Ω·cm. 11 It is made of ohm•m material and is disposed between the one or more cooling bodies (8) and the rear glass (3).

12. The solar module (1) according to claim 11, wherein the material of the highly electrically insulating layer (12) is any one of a ceramic material, a polymer having ceramic filler, and a silicone resin, wherein the ceramic material is at least one of AlN, Al2O3, Si3N4, MgO, and BN, the polymer is selected from a material composed of polyether ether ketone (PEEK) or polyamide 66 (PA66) and BN, Al2O3, or SiO2, and the silicone resin is a silicone adhesive or a silicone film.

13. The solar module (1) according to claim 11, wherein each of the one or more cooling bodies (8) is made of a metallic material and / or graphite, wherein the metallic material is at least one of aluminum, copper and magnesium alloys.

14. The solar module (1) according to claim 1, wherein each of the one or more cooling bodies (8) has a base (9) and a protrusion (10) protruding from the base, wherein heat conduction between the rear glass (3) and the one or more cooling bodies (8) takes place at the base (9).

15. The solar module (1) according to claim 14, wherein the thickness of each of the protrusions (10) is less than 2 mm, the distance between adjacent protrusions in the protrusions (10) is at least 0.5 mm, and the thickness of the base (9) is less than 0.2 mm.

16. The solar module (1) according to claim 15, wherein, The thickness of each of the protrusions (10) is less than 1 mm.

17. The solar module (1) according to claim 15, wherein, The thickness of each of the protrusions (10) is less than 0.5 mm.

18. The solar module (1) according to claim 15, wherein, The thickness of each of the protrusions (10) is less than 0.2 mm.

19. The solar module (1) according to claim 15, wherein, The thickness of each of the protrusions (10) is less than 0.08 mm.

20. The solar module (1) according to claim 15, wherein, The distance between adjacent protrusions in the protrusion (10) is at least 1 mm.

21. The solar module (1) according to claim 15, wherein, The distance between adjacent protrusions in the protrusion (10) is at least 2 mm.

22. The solar module (1) according to claim 15, wherein, The thickness of the base (9) is less than 0.1 mm.

23. The solar module (1) according to claim 15, wherein, The thickness of the base (9) is less than 0.05 mm.

24. The solar module (1) according to claim 14, wherein, The protrusion is a cooling rib or a cooling pin.

25. The solar module (1) according to claim 1, wherein, The distance between two adjacent cooling bodies in one or more cooling bodies (8) is 0.1 mm to 1 mm.

26. The solar module (1) according to claim 1, wherein, The distance between the cooling body (8) closest to the mounting element (6) for mounting the solar module (1) and the mounting element (6) is 1 mm to 20 mm.

27. The solar module (1) according to claim 1, wherein, The heat transfer coefficient of the solar module (1) is at least 20 W / (K•m). 2 ).

28. A method for manufacturing a solar module (1) according to any one of claims 1 to 27, comprising: A front glass (2) and a rear glass (3) are provided, the front glass and the rear glass being fixedly connected to each other by at least one intermediate layer (4), wherein a plurality of solar cells (5) connected in series are disposed between the front glass (2) and the rear glass (3). A passive cooling structure (7) having one or more cooling bodies (8) is bonded to the surface of the rear glass (3) away from the plurality of solar cells (5), wherein: The passive cooling structure (7) has a contact surface (13) at which it makes thermal contact with the rear glass (3) for heat conduction, wherein the contact surface (13) covers at least 90% of the photovoltaic active surface of the solar module (1); The area ratio of the surface of the passive cooling structure (7) away from the rear glass (3) to the contact surface (13) is at least 3; Each of the one or more cooling bodies is made of a material having a thermal conductivity to density ratio of at least 0.02 W•cm² / (g•K); The surface density of the passive cooling structure (7) is less than 0.6 g / cm³. 2 The mass surface density is the mass of the passive cooling structure (7) per unit contact area; The resistivity surface product of the passive cooling structure (7) is greater than 4 × 10⁻⁶. 11 ohm•cm², the resistivity surface product is the product of the contact area between the passive cooling structure (7) and the rear glass (3) and the electrical contact resistance.

29. The method according to claim 28, wherein, The area ratio of the surface of the passive cooling structure (7) away from the rear glass (3) to the contact surface (13) is at least 5.

30. The method according to claim 28, wherein, The area ratio of the surface of the passive cooling structure (7) away from the rear glass (3) to the contact surface (13) is greater than 7.

31. The method according to claim 28, wherein, Each of the one or more cooling bodies is made of a material having a thermal conductivity to density ratio of at least 0.05 W•cm² / (g•K).

32. The method according to claim 28, wherein, The surface density of the passive cooling structure (7) is less than 0.5 g / cm³. 2 .

33. The method according to claim 28, wherein, The surface density of the passive cooling structure (7) is less than 0.4 g / cm².

34. The method according to claim 28, wherein, The resistivity product of the passive cooling structure (7) is greater than 2 × 10⁻⁶. 12 ohm•cm².

35. The method according to claim 28, wherein, The resistivity product of the passive cooling structure (7) is greater than 1×10⁻⁶. 13 Ohm•cm².

36. Use of a solar module (1) according to any one of claims 1 to 27 as part of a building’s ventilated facade.

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