Thermochromic glass for automobile panoramic awning and manufacturing method of thermochromic glass
By combining thermochromic glass with thermochromic materials and low emissivity materials on the automotive panoramic skylight, adaptive adjustment of infrared light transmittance is achieved, solving the problem of insufficient dimming and thermal insulation performance in the prior art, and improving the Insulation and insulation effects and simplify system design.
Patent Information
- Application Number
- CN202411421134.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2024-12-20
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The dimming and thermal insulation performance of existing automotive panoramic skylights is limited, making it difficult to meet the increasing driving comfort needs, and existing dimmable technology requires additional power supply or electronic control systems to increase system complexity.
Using thermochromic glass that combines thermochromic materials and low emissivity materials, adaptive adjustment is achieved by coating low emissivity layers and thermochromic layers on both sides of tempered glass. Infrared light transmittance reduces the emission rate of infrared band light in the car.
It realizes adaptive adjustment of solar radiation outside the vehicle under different temperature environments, improves the insulation and insulation effect of the panoramic sky curtain of the car, avoids additional electric heating devices and electronic control systems, and simplifies system design.
Smart Images
Figure CN119161113A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to tempered glass, in particular to thermochromic glass for automobile panoramic skylight and a manufacturing method thereof. Background Art
[0002] Against the backdrop of intelligent development of new energy vehicles, panoramic skylights are gradually being used in high-end new energy vehicle models because they can enhance the sense of cabin space, reduce roof costs, and achieve vehicle differentiation. An ideal automotive panoramic skylight should have the function of seasonally adjusting infrared light transmittance while ensuring daylighting and visual experience. That is, in summer, it can block more infrared light from entering the car to achieve a heat-insulating effect, while in winter, it can reduce the loss of infrared light in the car to achieve a heat-insulating effect. In the existing technology, automotive skylights usually use tempered glass, but its dimming and heat-insulating properties are limited, making it difficult to meet the increasing demand for driving comfort. In addition, the current existing technology for dimmable automotive skylights is mainly based on electrochromic dimming films, which require additional power supplies or electronic control systems to achieve dimming functions, thereby increasing the complexity of the system.
[0003] Vanadium dioxide (VO2) is a typical inorganic thermochromic material. At high temperatures, it is in a metallic state and presents a tetragonal rutile phase. It is optically translucent to visible light and opaque to infrared light, and its phase transition temperature is about 68°C. At temperatures below 68°C, a phase transition occurs, transforming it into a semiconductor state and presenting a monoclinic phase. It is optically translucent to visible light and highly transparent to infrared light. Therefore, VO2 can be used in panoramic sunroofs of cars, and thermochromism can be achieved by adaptively changing the temperature according to the ambient temperature without the need for a power supply or electronic control system. However, the phase transition temperature of single VO2 is much higher than the comfortable temperature inside the car. Therefore, it is necessary to further regulate the phase transition temperature of VO2 so that it can be used in panoramic sunroofs. Summary of the Invention
[0004] Purpose of the invention: The purpose of the present invention is to provide a thermochromic glass for a panoramic sunroof of an automobile that can realize adaptive adjustment of surface emissivity and has the function of seasonal adjustment of infrared light transmittance, and a method for manufacturing the same.
[0005] Technical solution: The thermochromic glass of the present invention comprises tempered glass, wherein low-emissivity layers with an emissivity of 0.20-0.50 are coated on both sides of the tempered glass, and an adhesive layer and a thermochromic layer are sequentially coated on the surface of one of the low-emissivity layers.
[0006] Preferably, the emissivity of the low emissivity layer is 0.25-0.3.
[0007] Preferably, the low emissivity layer is a metal or metal compound film.
[0008] Further preferably, the material of the low emissivity layer is one or two of Ag, Cu, Al, TiO2, In2O3 and SnO2, preferably Ag.
[0009] Preferably, the emissivity of the low emissivity layer is 0.25-0.30.
[0010] Preferably, the thermochromic layer comprises an inorganic thermochromic material and a base material.
[0011] Preferably, the phase transition temperature of the inorganic thermochromic material is close to room temperature.
[0012] Preferably, the main component of the inorganic thermochromic material is VO2, and the doping element is one or two of W, Mo, F, Zr, and Mg.
[0013] Preferably, the mass ratio of the doping element in the inorganic thermochromic material is 1 wt%-10 wt%, preferably 5 wt%.
[0014] Preferably, the base material is one of polymethyl methacrylate, polydimethylsiloxane, polyurethane, polyvinyl alcohol, and polyvinylidene fluoride.
[0015] The method for preparing the thermochromic glass comprises the following steps:
[0016] Step 1: Coat a low emissivity layer on both the inner and outer surfaces of the tempered glass.
[0017] Step 2: dissolving the base material in a solvent to form a sol, coating the solvent as an adhesive layer on the surface of one of the low emissivity layers and curing the solvent.
[0018] Step three: uniformly mix the thermochromic material doped with element W and the sol-like base material, apply the thermochromic layer as a thermochromic layer to the surface of the adhesive layer, and solidify it.
[0019] Preferably, the mass ratio of the doping element W in the thermochromic material is 5 wt %; after being mixed with the base material, the mass ratio of the thermochromic material is 10 wt %.
[0020] Preferably, the solvent in step 1 is one of deionized water, anhydrous ethanol, acetone, butanone, and dimethylformamide, preferably acetone or butanone.
[0021] Preferably, the coating method in step 1 is sputtering.
[0022] Preferably, the coating method in step 2 and step 3 is one of spin coating, spray coating, and natural casting, preferably spin coating.
[0023] Preferably, the curing method in step 2 and step 3 is natural air drying or hot plate heating, preferably natural air drying.
[0024] Preferably, in step three, after the thermochromic material and the base material are mixed, the mass ratio of the thermochromic material is 2 wt % to 40 wt %, preferably 2 wt % to 10 wt %.
[0025] Principle of the Invention: This invention provides thermochromic glass capable of adaptively adjusting surface emissivity. Combining a thermochromic material with a low-emissivity material, the glass is used in automotive panoramic sunroofs, enabling adaptive surface emissivity adjustment, resulting in more efficient thermal insulation and heat preservation. The inorganic thermochromic material has a phase transition temperature near room temperature, while the low-emissivity material reduces the emissivity of infrared light within the vehicle. When used in automotive panoramic sunroofs, when the ambient temperature is above the phase transition temperature of the thermochromic material, the material effectively blocks infrared light from entering the vehicle interior by increasing its infrared emissivity, thereby maintaining a cool interior. When the temperature is below the phase transition temperature, the material becomes transparent, allowing infrared light from outside to enter the vehicle interior, raising the interior temperature. Simultaneously, the low-emissivity layers on both sides of the glass reduce the emissivity of infrared light within the vehicle interior, thereby maintaining a warm interior.
[0026] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The thermochromic glass of the present invention combines thermochromic materials and low-emissivity materials together, and is applied to the panoramic sunroof of a car, which can realize the function of adaptively adjusting the surface emissivity, so that the panoramic sunroof of the car has a more efficient heat insulation and thermal insulation effect; (2) The phase transition temperature of the inorganic thermochromic material used in the thermochromic glass of the present invention is close to room temperature, and no additional electric heating device is required when applied to the panoramic sunroof; (3) The optical properties of the inorganic thermochromic material used in the thermochromic glass of the present invention have temperature response characteristics, that is, it has high transmittance for infrared light below the phase transition temperature and high barrier characteristics above the phase transition temperature. This characteristic helps the panoramic sunroof to have the function of adaptively adjusting the solar radiation outside the car under different temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 Schematic diagram of the structure of the thermochromic glass of the present invention;
[0028] Figure 2 This is a schematic diagram of the cooling and heat preservation principle when the outside temperature of the vehicle is higher than the phase transition temperature of the thermochromic glass according to the present invention;
[0029] Figure 3This is a schematic diagram of the cooling and heat preservation principle when the outside temperature of the vehicle is lower than the phase transition temperature of the thermochromic glass according to the present invention. DETAILED DESCRIPTION
[0030] The technical solution of the present invention will be further described below in conjunction with embodiments.
[0031] Example 1
[0032] like Figure 1 As shown, the thermochromic glass of the present invention includes a tempered glass 1, and a low emissivity layer 2 with an emissivity of 0.25-0.30 is coated on both sides of the tempered glass 1, and an adhesive layer 3 and a thermochromic layer 4 are sequentially coated on the surface of one of the low emissivity layers 2.
[0033] The low emissivity layer 2 is formed by sputtering silver onto the inner and outer surfaces of the tempered glass 1 .
[0034] The thermochromic layer 4 includes an inorganic thermochromic material and a base material.
[0035] The main component of the inorganic thermochromic material is VO2, and the doping element is W.
[0036] The method for preparing the thermochromic glass comprises the following steps:
[0037] Step 1: A layer of Ag film with a thickness of 300 nm is coated on both surfaces of the tempered glass 1 by sputtering to serve as the low emissivity layer 2 .
[0038] Step 2: dissolve the base material PMMA in acetone solvent to make it into a sol state, and spin-coat it as an adhesive layer 3 onto the surface of one of the low-emissivity layers 2, and then solidify it.
[0039] Step 3: Mix the W-doped thermochromic material VO2 with the sol-like PMMA, apply the resulting mixture as the thermochromic layer 4 to the adhesive layer 3, and cure. The W-doped thermochromic material comprises 5% by weight. After mixing with the base material, the thermochromic material accounts for 10% by weight.
[0040] The phase transition temperature of doped VO2 was tested using differential scanning calorimetry.
[0041] The phase transition temperature of the thermochromic material prepared in this embodiment is 33° C., which is close to room temperature.
[0042] The emissivity of the surface of ordinary tempered glass is about 0.84, while the surface emissivity of the low emissivity layer of the present invention is 0.25-0.3 (related to the metal layer sputtered on the surface).
[0043] like Figure 2-3As shown, the thermochromic glass of the present invention, when used as a panoramic sunroof for automobiles, operates on the following principles for cooling and insulating the vehicle: During use, one surface with the thermochromic layer is placed outside the vehicle, while the other surface is placed inside. When the ambient temperature outside the vehicle is higher than the phase transition temperature of the thermochromic material in the thermochromic layer, the exterior glass surface assumes a high-emissivity state, while the interior glass surface assumes a low-emissivity state. The thermochromic material effectively blocks infrared light from entering the vehicle interior by increasing its infrared emissivity, thereby maintaining a cool interior. When the ambient temperature is lower than the phase transition temperature of the thermochromic material, both the interior and exterior glass surfaces assume a low-emissivity state, allowing infrared light from outside to enter the vehicle interior, raising the interior temperature. Simultaneously, the low-emissivity layers on both glass surfaces reduce the emissivity of the interior infrared band, thereby maintaining a cool interior.
[0044] Comparative Example 1: Car panoramic skylight without low emissivity layer
[0045] In this comparative example, the same parts as those in Example 1 are not described again. The difference is that the thermochromic glass only includes the thermochromic layer 4 and is not coated with the low-emissivity layer 2.
[0046] The thermochromic glass comprises a tempered glass 1 , on the surface of which an adhesive layer 3 and a thermochromic layer 4 are sequentially coated.
[0047] The phase transition temperature of the thermochromic material prepared in this comparative example is 33°C.
[0048] Working principle:
[0049] When the temperature outside the car is higher than 33°C, the thermochromic layer will undergo a phase change, changing its infrared emissivity, thereby blocking some infrared light from entering the car, which has a certain cooling effect; when the temperature outside the car is lower than 33°C, the thermochromic layer will return to a low emissivity state, allowing more infrared light to pass through the glass into the car, which has a certain thermal insulation effect.
[0050] Comparative Example 2: Car panoramic sunroof without thermochromic layer
[0051] In this comparative example, the same parts as those in Example 1 are not described again. The difference is that the thermochromic glass only includes the low-emissivity layer 2 but does not include the thermochromic layer 4.
[0052] The thermochromic glass comprises a tempered glass 1 , on both sides of which a 300 nm thick Ag film is coated as a low emissivity layer 2 , and the emissivity thereof is 0.25-0.30.
[0053] Working principle:
[0054] The low-emissivity layer reduces the loss of infrared radiation inside the car by reflecting infrared light, thus achieving a certain thermal insulation effect. However, due to the lack of the function of adjusting the transmittance of infrared light, this structure cannot block the incidence of infrared light outside the car in a high-temperature environment, and therefore cannot effectively reduce the temperature inside the car.
[0055] Under the same conditions, the interior temperature of the vehicle of Example 1 and Comparative Examples 1-2 was tested, and the results were as follows:
[0056] (1) In summer, when the outdoor temperature is approximately 35°C, the vehicle's doors and windows are all closed, the vehicle's air conditioning is turned off for external ventilation, and the vehicle is left unattended in an open-air environment for 1 hour. The vehicle's interior ambient temperature is measured after the vehicle is parked in an open-air environment. When the skylight of the present invention (Example 1) is used in the vehicle, the interior ambient temperature is approximately 5°C lower than that of a panoramic skylight having only a low-emissivity layer (Comparative Example 2) and is approximately the same as that of a panoramic skylight having only a thermochromic layer (Comparative Example 1).
[0057] (2) In winter, when the outdoor temperature is approximately -5°C, the vehicle interior temperature is adjusted to 24°C using the vehicle air conditioner. The vehicle is left to rest in the open air for 1 hour, and the interior temperature is measured. When the skylight of the present invention (Example 1) is used in a vehicle, the interior temperature is 2°C higher than that of a panoramic skylight having only a thermochromic layer (Comparative Example 1), and is approximately the same as that of a panoramic skylight having only a low-emissivity layer (Comparative Example 2).
[0058] Compared to traditional tempered glass, the glass produced in Comparative Example 1 has some ability to adjust infrared light transmittance, but the overall effect is inferior to that of the embodiments of the present invention. Due to the lack of a low-emissivity layer, this structure relies solely on the phase change properties of the thermochromic layer, failing to effectively reduce the loss of infrared radiation from the vehicle interior. Consequently, its insulation performance is poor in winter. Furthermore, its thermal insulation performance is limited in summer, making it difficult to significantly reduce the interior temperature of the vehicle.
[0059] Compared to traditional skylights, the glass produced in Comparative Example 2 offers some insulation, but lacks the adaptive adjustment capabilities of the thermochromic layer, resulting in weaker overall insulation. While it can provide some insulation in winter by reducing the loss of infrared radiation from the vehicle interior, in summer, significant amounts of infrared light from outside still enter the vehicle interior, resulting in poor insulation and failing to meet comfort requirements in high-temperature environments.
[0060] Summary and comparison:
[0061] A skylight with only a thermochromic layer can adjust the transmittance of infrared light to a certain extent, but due to the lack of a low-emissivity layer, it cannot reduce the loss of infrared radiation inside the car and has insufficient thermal insulation capabilities. A skylight with only a low-emissivity layer can reduce the loss of infrared radiation inside the car and has a thermal insulation effect, but due to the lack of a thermochromic layer, it cannot effectively block infrared light outside the car and has poor thermal insulation performance. In contrast, the present invention combines a thermochromic layer and a low-emissivity layer to form thermochromic glass as a panoramic skylight for a car. This can not only block external infrared light from entering the car in a high-temperature environment, thereby achieving a cooling effect, but can also reduce the loss of infrared radiation inside the car in a low-temperature environment, achieving a good thermal insulation effect, and has significant technical advantages.
Claims
1. A thermochromic glass comprising tempered glass (1), It is characterized in that Low emissivity layers (2) with an emissivity of 0.20-0.50 are coated on both sides of the tempered glass (1), and an adhesive layer (3) and a thermochromic layer (4) are sequentially coated on the surface of one of the low emissivity layers (2).
2. The thermochromic glass according to claim 1, It is characterized in that The emissivity of the low emissivity layer (2) is 0.25-0.
3.
3. The thermochromic glass according to claim 1, It is characterized in that The material of the low emissivity layer (2) is Ag, Cu, Al, TiO 2 、In 2 O 3 and SnO 2 One or both of these.
4. The thermochromic glass according to claim 1, It is characterized in that The thermochromic layer (4) comprises an inorganic thermochromic material and a base material, and the phase change temperature of the inorganic thermochromic material is close to room temperature.
5. The thermochromic glass according to claim 4, It is characterized in that The main component of the inorganic thermochromic material is VO 2 The doping elements are one or two of W, Mo, F, Zr, and Mg.
6. The thermochromic glass according to claim 5, It is characterized in that The mass ratio of the doping element in the inorganic thermochromic material is 1wt%-10wt%.
7. The thermochromic glass according to claim 4, It is characterized in that The base material is one of polymethyl methacrylate, polydimethylsiloxane, polyurethane, polyvinyl alcohol and polyvinylidene fluoride.
8. A method for preparing the thermochromic glass according to claim 1, It is characterized in that The following steps are involved: Step 1: Coating a low emissivity layer on both the inner and outer surfaces of the tempered glass; Step 2, dissolving the base material in a solvent to make it in a sol state, coating it on the surface of one of the low emissivity layers as an adhesive layer, and then curing it; Step three: evenly mix the element-doped thermochromic material with the sol-like base material, apply it to the surface of the adhesive layer and solidify it.
9. The preparation method according to claim 8, It is characterized in that In step 2 and step 3, the coating method is one of spin coating, spray coating, and natural casting; the curing method is natural air drying or hot plate heating.
10. The preparation method according to claim 8, It is characterized in that After the thermochromic material and the base material are mixed, the mass ratio of the thermochromic material is 2wt%-40wt%.