Photovoltaic flexible energy storage power cable

Abstract

The application provides a photovoltaic flexible energy storage power cable, and relates to the technical field of power cables.The application comprises a main body mechanism, a snake bone bending mechanism and a protection mechanism.The snake bone bending mechanism comprises a shielding layer, two temperature measuring optical fibers, a semiconductor refrigerating sheet, two heat conducting strips, a group of temperature control rings, a group of annular skeletons and a group of filling capsules.The application can control the reversible melting and solidification of the phase change material in the filling capsules under the precise temperature control of the semiconductor refrigerating sheet and the heat conducting ring, thereby driving and locking the mutual positions of the annular skeletons, greatly reducing the complexity and labor cost of installation, avoiding the problems of sheath pressure injury, stress concentration and form failure caused by tool aging and loosening due to external binding, and enabling the form resetting through temperature control again, thereby endowing the cable with the ability of repeated shaping and self-adaptive laying path, and significantly improving the installation flexibility, form stability and long-term operation reliability of the cable in a complex photovoltaic station.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cable technology, and in particular to a photovoltaic flexible energy storage power cable. Background Technology

[0002] Photovoltaic cables are special cables designed specifically for solar photovoltaic power generation systems. They are mainly used to transmit DC power generated by photovoltaic modules safely and for a long time in harsh outdoor environments. They connect key equipment such as photovoltaic panels, combiner boxes, inverters, and power distribution devices. Their structural design emphasizes flexibility and mechanical strength, and can resist bending, torsion, tension, and thermal expansion and contraction caused by climate change during installation and use. They also pass rigorous weather resistance tests to prevent cracking or performance degradation caused by environmental stress. Their core mission is to maintain stable insulation resistance and low transmission loss under complex climatic conditions such as strong sunlight, rain, snow, salt spray, and humidity. They are an indispensable special component for achieving safe, efficient, and long-lasting power transmission in photovoltaic systems.

[0003] During the installation and laying of photovoltaic cables in photovoltaic power plants, they often need to be bent and fixed in a specific shape according to the on-site support structure, route changes, or to avoid obstacles. However, to improve their torsion resistance, fatigue resistance, and long-term reliability, the photovoltaic cables currently widely used mostly adopt highly elastic insulation and sheath materials, and are often supplemented with spiral winding or stranded internal reinforcement structures. This makes it difficult for the cables to maintain the required bending angle or arc during construction. Construction workers must rely on external tools such as cable ties, clips, binding wires, or special clamps to forcibly bind and limit them in order to fix the bending shape. This not only increases the complexity and time of installation and raises the cost of manpower and auxiliary materials, but also causes potential damage to the cable sheath or creates fixed stress points due to the pressure concentration or long-term aging and loosening of the external binding tools, affecting the long-term stability and safety of the cable. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a photovoltaic flexible energy storage power cable that can solve the technical problems of the prior art, such as the inability to fix the cable in a bending shape, which increases the installation time and cost and causes damage to the cable.

[0005] This invention proposes a photovoltaic flexible energy storage power cable, comprising: a main body structure, a serpentine bending mechanism, and a protective mechanism; The serpentine bending mechanism includes a shielding layer, two temperature-sensing optical fibers, a semiconductor cooling chip, two heat-conducting strips, a set of temperature-controlling rings, a set of annular skeletons, and a set of filling bladders. The two temperature-sensing optical fibers are fixedly inserted inside the shielding layer. The two heat-conducting strips are fixedly installed on the outer wall of the shielding layer. A set of temperature-controlling rings is fixedly fitted onto the outer wall of the shielding layer. The set of temperature-controlling rings is fixedly installed between the outer walls of the two heat-conducting strips. A set of annular skeletons is fixedly fitted between the outer walls of the two heat-conducting strips. The outer wall of each of the filling bladders is adhered to the outer wall of the annular skeleton. The outer wall of each of the temperature-controlling rings is in contact with the outer wall of the filling bladder.

[0006] Preferably, the heat-conducting strip includes a heat pipe and a heat insulation sleeve, with the heat pipe fixedly inserted inside the heat insulation sleeve.

[0007] Preferably, the temperature control ring includes a thermally conductive copper ring and a heat insulation ring, wherein the thermally conductive copper ring is fixedly sleeved on the outer wall of the heat insulation ring.

[0008] Preferably, the snake-bone bending mechanism has a main body mechanism fixedly inserted inside, the main body mechanism including a set of conductors, a set of insulating layers, a filling layer, a heat-conducting layer and a pressure detection optical fiber.

[0009] Preferably, a group of insulating layers are all sleeved on the outer wall of the conductor, and a filling layer is fixedly sleeved between the outer walls of the group of insulating layers.

[0010] Preferably, a filling layer is fixedly inserted inside the thermally conductive layer, and the pressure detection optical fiber is fixedly inserted inside the filling layer.

[0011] Preferably, the outer wall of the snake-bone bending mechanism is fixedly fitted with a protective mechanism, which includes an elastic damping layer, a fireproof layer, and a protective layer.

[0012] Preferably, the fireproof layer is fixedly sleeved on the outside of the elastic damping layer, and a protective layer is fixedly sleeved on the outer wall of the fireproof layer.

[0013] Preferably, the protective layer includes a biological repellent layer, a physical protective layer, and a reflective coating, wherein the physical protective layer is fixedly fitted onto the outer wall of the biological repellent layer.

[0014] Preferably, the outer wall of the physical protective layer is provided with a reflective coating, the coating containing thermochromic material components and highly reflective metal oxide particles.

[0015] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: In this embodiment of the invention, the phase change material inside the cable filling bladder can undergo reversible melting and solidification under the precise temperature control of the semiconductor cooling chip and the heat-conducting ring, thereby driving and locking the relative positions of the annular skeleton. This process is completed entirely by the cable's built-in temperature control system, without the need for external auxiliary tools such as cable ties and clips. This not only significantly reduces the complexity and labor costs of installation, but also avoids problems such as sheath damage, stress concentration, and shape failure caused by tool aging and loosening due to external binding. At the same time, this mechanism is reversible and can achieve shape reset by temperature control again, giving the cable the ability to be repeatedly shaped and adapt to the laying path, significantly improving the installation flexibility, shape stability, and long-term operational reliability of the cable in complex photovoltaic sites. Attached Figure Description

[0016] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0017] Figure 1 This is a structural schematic diagram of a photovoltaic flexible energy storage power cable provided in an embodiment of the present invention.

[0018] Figure 2 This is a three-dimensional schematic diagram of the main structure of a photovoltaic flexible energy storage power cable provided in an embodiment of the present invention.

[0019] Figure 3 This is a perspective view of a serpentine bending mechanism for a photovoltaic flexible energy storage power cable provided in an embodiment of the present invention.

[0020] Figure 4 This is an internal structural diagram of a serpentine bending mechanism for a photovoltaic flexible energy storage power cable provided in an embodiment of the present invention.

[0021] Figure 5 This is a three-dimensional schematic diagram of a serpentine bending mechanism for a photovoltaic flexible energy storage power cable provided in an embodiment of the present invention.

[0022] Figure 6 This is a cross-sectional view of a serpentine bending mechanism and a protective mechanism for a photovoltaic flexible energy storage power cable provided in an embodiment of the present invention.

[0023] Figure 7 This is a plan view of a photovoltaic flexible energy storage power cable provided in an embodiment of the present invention.

[0024] Explanation of reference numerals in the attached drawings: 1-Main structure; 11-Conductor; 12-Insulation layer; 13-Filling layer; 14-Heat-conducting layer; 15-Pressure detection optical fiber; 2-Snake-bending mechanism; 21-Shielding layer; 22-Temperature-sensing optical fiber; 23-Semiconductor cooling chip; 24-Heat-conducting strip; 241-Heat pipe; 242-Heat insulation sleeve; 25-Temperature control ring; 251-Heat-conducting copper ring; 252-Heat insulation ring; 26-Annular skeleton; 27-Filling bladder; 3-Protective mechanism; 31-Elastic shock-absorbing layer; 32-Fireproof layer; 33-Protective layer; 331-Biological repellency layer; 332-Physical protective layer; 333-Reflective coating. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0026] Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts disclosed in this invention.

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention.

[0028] Reference manual attached Figures 1 to 7 The present invention provides a structure for a photovoltaic flexible energy storage power cable, comprising: a main body structure 1, a serpentine bending mechanism 2, and a protective mechanism 3; The snake-bone bending mechanism 2 includes a shielding layer 21, two temperature-sensing optical fibers 22, a semiconductor cooling chip 23, two heat-conducting strips 24, a set of temperature-controlling rings 25, a set of annular skeletons 26, and a set of filling bladders 27. The two temperature-sensing optical fibers 22 are fixedly inserted inside the shielding layer 21. The two heat-conducting strips 24 are fixedly installed on the outer wall of the shielding layer 21. A set of temperature-controlling rings 25 are fixedly fitted on the outer wall of the shielding layer 21. The set of temperature-controlling rings 25 are fixedly installed between the outer walls of the two heat-conducting strips 24. A set of annular skeletons 26 are fixedly fitted between the outer walls of the two heat-conducting strips 24. The outer wall of each of the filling bladders 27 is adhered to the outer wall of the annular skeleton 26. The outer wall of each of the temperature-controlling rings 25 is in contact with the outer wall of the filling bladder 27.

[0029] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: In this embodiment of the invention, the filling bladder 27 is filled with a phase change material. Under normal cable conditions, the phase change material inside the filling bladder 27 is in a solidified state, causing multiple annular skeletons 26 to be arranged in a longitudinal straight line. At this time, the cable is in a horizontal state. When the cable needs to be bent, the user first activates the semiconductor cooling chip 23. At this time, one side of the semiconductor cooling chip 23 near the two heat-conducting strips 24 begins to heat up, while the other side begins to cool down. The heated surface transfers heat to the heat-conducting strips 24. The heat-conducting strips 24 have good thermal conductivity and can quickly transfer heat to the multiple temperature-controlling rings 25 in contact with them. At this time, the temperature-controlling rings 25 begin to heat up. Since the temperature-controlling rings 25 are in contact with the top filling bladder 27 and are filled with... Only the bottom surface of the filling bladder 27, which contacts the temperature control ring 25, is made of non-insulating material. Therefore, the high-temperature temperature control ring 25 melts the solid phase change material inside. The molten phase change material flows inside the filling bladder 27, facilitating the movement of the annular frame 26. At this point, the user bends the entire cable according to actual working needs, causing the bent portion of the annular frame 26 to move. The inner sides of the annular frames 26 move closer together, squeezing the filling bladder 27 in the middle, reducing its volume and pushing the phase change liquid away. Meanwhile, the outer sides of the annular frames 26 move away from each other. At this time, the phase change material squeezed inside the filling bladder 27 begins to flow to this point, causing the filling bladder 27 to expand. After the cable is bent, the user changes the semiconductor... The current flowing through the cooling element 23 causes a change in the hot and cold surfaces, with the side closer to the heat-conducting strip 24 cooling down. The heat-conducting strip 24, with the aid of its fixed temperature control ring 25, begins to absorb heat from the filling chamber 27, causing the phase change material to rapidly cool and solidify, maintaining its current shape. This fixes the positions of the multiple ring-shaped frames 26 and keeps the cable in a bent state. The entire process requires no external tools, greatly simplifying the installation process, reducing reliance on auxiliary tools and costs, and avoiding the risks of sheath damage, stress concentration, and morphological failure caused by concentrated pressure or long-term aging and loosening of external binding tools. This ensures the long-term reliability and stability of the cable in a bent state. Reversible, the cable can be reshaped by local heating when readjustment is needed, giving it intelligent adaptability to be repeatedly reshaped. The temperature-sensing fiber optic 22 is used to monitor the surrounding temperature in real time, which makes it convenient to accurately control the heating or cooling power of the semiconductor cooling chip 23, so that the phase change material can melt or solidify within a set time, preventing rigid failure caused by accidental heating or loss of flexibility caused by accidental cooling, and ensuring the smooth progress of the entire operation. The shielding layer 21 can effectively block external electromagnetic interference, prevent power grid noise, radiation and other factors from affecting the purity of internal power transmission, and also prevent noise generated by the cable's own control circuit from leaking out and interfering with other equipment. It can also delay insulation aging through a uniform electric field.

[0030] In one possible implementation, the heat-conducting strip 24 includes a heat pipe 241 and a heat insulation sleeve 242, with the heat pipe 241 fixedly inserted inside the heat insulation sleeve 242.

[0031] In this embodiment of the invention, a heat pipe 241 is used to achieve the heat transfer structure, which effectively improves the speed and efficiency of heat transfer. At the same time, the heat insulation sleeve 242 wrapped around the outer wall of the heat pipe 241 not only prevents heat loss during the transfer process, but also effectively prevents external heat or heat generated during cable operation from being transferred to the heat pipe 241, which could lead to the accidental melting of the phase change material and cause sudden deformation of the cable.

[0032] In one possible implementation, the temperature control ring 25 includes a thermally conductive copper ring 251 and a heat insulation ring 252, with the thermally conductive copper ring 251 fixedly sleeved on the outer wall of the heat insulation ring 252.

[0033] In this embodiment of the invention, the heat-conducting copper ring 251 is made of pure copper and has good thermal conductivity, which can quickly melt or solidify the phase change material inside the filling bladder 27. The heat insulation ring 252 at the bottom of the heat-conducting copper ring 251 effectively prevents the heat generated during cable operation from being transferred to the surface of the heat-conducting copper ring 251, ensuring that the cable is always stable in the preset bending state.

[0034] In one possible implementation, a main body mechanism 1 is fixedly inserted inside the snake-bone bending mechanism 2. The main body mechanism 1 includes a set of conductors 11, a set of insulating layers 12, a filling layer 13, a heat-conducting layer 14, and a pressure detection optical fiber 15.

[0035] In this embodiment of the invention, the entire main body 1 is the core structure, realizing the basic power transmission function of the power cable.

[0036] In one possible implementation, a set of insulating layers 12 are all sleeved on the outer wall of the conductor 11, and a filling layer 13 is fixedly sleeved between the outer walls of the set of insulating layers 12.

[0037] In this embodiment of the invention, the inner insulation layer 12 is made of a special cross-linked polyolefin high-performance material, which can maintain excellent electrical insulation performance and long-term stability even under extreme environmental conditions. This layer can effectively isolate the conductor 11, prevent current leakage or short circuit, and provide a basic guarantee for the safe and stable operation of the entire photovoltaic system. The filling layer 13 mainly plays the role of structural support, buffering and stabilization. It can fix the relative position of multiple wire cores and prevent them from shifting or rubbing against each other during use or installation due to vibration or bending. It also helps to maintain the roundness of the cable cross section, optimize the uniformity of the outer sheath, and improve the overall mechanical properties and torsional resistance of the cable.

[0038] In one possible implementation, a filling layer 13 is fixedly inserted inside the heat-conducting layer 14, and a pressure-detecting optical fiber 15 is fixedly inserted inside the filling layer 13.

[0039] In this embodiment of the invention, the heat-conducting layer 14 is made of a material with high thermal conductivity. Its core function is to quickly dissipate the heat generated by the conductor 11 during operation from the inside, avoiding the risk of local overheating, accelerated insulation aging, or even thermal breakdown caused by heat accumulation. The heat-conducting layer 14 can improve the actual current carrying capacity of the cable and maintain stable electrical performance. The pressure detection optical fiber 15 integrated inside the cable can measure mechanical stress such as external extrusion, impact, and excessive bending, enabling maintenance personnel to promptly detect potential structural damage to the cable caused by improper laying bending, external pressure, or geological disasters, and prevent faults caused by insulation damage or conductor 11 deformation, greatly improving the reliability and safety of the photovoltaic cable system.

[0040] In one possible implementation, a protective mechanism 3 is fixedly fitted on the outer wall of the snake-bone bending mechanism 2. The protective mechanism 3 includes an elastic damping layer 31, a fireproof layer 32, and a protective layer 33.

[0041] In this embodiment of the invention, the protective mechanism 3, as the outermost structure, effectively prevents the cable from being damaged by external forces, thus ensuring the stability of the cable.

[0042] In one possible implementation, the fireproof layer 32 is fixedly sleeved on the outside of the elastic damping layer 31, and the outer wall of the fireproof layer 32 is fixedly sleeved with a protective layer 33.

[0043] In this embodiment of the invention, when the cable is subjected to external impact, high-frequency vibration, periodic bending or compression, the elastic damping layer 31 efficiently absorbs and disperses mechanical energy through its own elastic deformation, preventing energy from being directly transferred to the internal conductor 11, and significantly reducing the risk of internal fracture due to vibration fatigue. The fireproof layer 32 is made of ceramicized silicone rubber, which actively blocks the spread of flames and maintains the line function when the cable is exposed to fire or high temperature, thus buying valuable time for fire warning, personnel evacuation and emergency power supply of critical power circuits in photovoltaic power plants. The protective layer 33 can effectively ensure the physical integrity and functional reliability of the cable throughout its entire life cycle, thereby extending the service life of the cable.

[0044] In one possible implementation, the protective layer 33 includes a biological repellency layer 331, a physical protective layer 332, and a reflective coating 333, with the physical protective layer 332 fixedly fitted onto the outer wall of the biological repellency layer 331.

[0045] In this embodiment of the invention, the biological repellent layer 331 is made by uniformly compounding natural repellents such as capsaicin and menthol or specific synthetic preparations into an elastic polymer matrix using microencapsulation technology. When an animal bites the cable, the outer layer ruptures, causing the microcapsules to rapidly release a strong pungent odor substance, which acts on the animal's olfactory and gustatory receptors, causing discomfort and prompting the animal to give up the attack. Without affecting the cable's flexibility and environmental safety, this avoids the risk of sheath damage, insulation exposure, or even short circuits caused by animal behavior. The physical protective layer 332 uniformly disperses high-hardness, wear-resistant micron-sized inorganic particles in the matrix material. When subjected to scratches or crushes from sharp objects, the hard particles can effectively share and resist stress, greatly improving the surface's scratch and cut resistance. When an animal bites this layer, these uniformly distributed hard particles can generate a continuous gritty sensation and damping when the teeth bite, greatly reducing the animal's biting efficiency and willingness.

[0046] In one possible implementation, the outer wall of the physical protective layer 332 is provided with a reflective coating 333, the coating containing thermochromic material components and highly reflective metal oxide particles.

[0047] In this embodiment of the invention, the highly reflective metal oxide particles inside the reflective coating 333 can efficiently reflect infrared and ultraviolet rays in sunlight, significantly reducing the surface temperature and internal heat load of the cable, and reducing damage caused by ultraviolet rays. The thermochromic material causes the coating color to change reversibly with temperature, showing obvious color difference when local overheating occurs, thereby providing intuitive overheating location and early warning for inspection, realizing surface protection that integrates passive cooling and active monitoring.

[0048] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the preferred embodiments, while those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A photovoltaic flexible energy storage power cable, characterized in that, include: The main structure (1), the snake-bone bending mechanism (2), and the protective mechanism (3); The snake-bone bending mechanism (2) includes a shielding layer (21), two temperature-sensing optical fibers (22), a semiconductor cooling chip (23), two heat-conducting strips (24), a set of temperature-controlling rings (25), a set of annular skeletons (26), and a set of filling bags (27). The two temperature-sensing optical fibers (22) are fixedly inserted inside the shielding layer (21). The two heat-conducting strips (24) are fixedly installed on the outer wall of the shielding layer (21). A set of temperature-controlling rings (25) is fixedly sleeved on the outer wall of the shielding layer (21). The set of temperature-controlling rings (25) is fixedly installed between the outer walls of the two heat-conducting strips (24). A set of annular skeletons (26) is fixedly sleeved between the outer walls of the two heat-conducting strips (24). The outer wall of each of the filling bags (27) is bonded to the outer wall of the annular skeleton (26). The outer wall of each of the temperature-controlling rings (25) is in contact with the outer wall of the filling bag (27). The filling bladder (27) is filled with phase change material. The semiconductor cooling chip (23) heats or cools the temperature control ring (25) through the heat conduction strip (24), so that the phase change material in the filling bladder (27) melts when heated or solidifies when cooled. After the phase change material melts, it flows inside the filling bladder (27), allowing the annular skeleton (26) to move relative to each other. After the phase change material solidifies, it fixes the relative positions of the multiple annular skeletons (26), keeping the cable in a bent state.

2. The photovoltaic flexible energy storage power cable according to claim 1, characterized in that, The heat-conducting strip (24) includes a heat pipe (241) and a heat insulation sleeve (242), with the heat pipe (241) fixedly inserted inside the heat insulation sleeve (242).

3. The photovoltaic flexible energy storage power cable according to claim 1, characterized in that, The temperature control ring (25) includes a thermally conductive copper ring (251) and a heat insulation ring (252), wherein the thermally conductive copper ring (251) is fixedly sleeved on the outer wall of the heat insulation ring (252).

4. The photovoltaic flexible energy storage power cable according to claim 1, characterized in that, The snake-bone bending mechanism (2) has a main body mechanism (1) fixedly inserted inside. The main body mechanism (1) includes a set of conductors (11), a set of insulation layers (12), a filling layer (13), a heat-conducting layer (14), and a pressure detection optical fiber (15).

5. The photovoltaic flexible energy storage power cable according to claim 4, characterized in that, A set of insulating layers (12) are all sleeved on the outer wall of the conductor (11), and a filling layer (13) is fixedly sleeved between the outer walls of the set of insulating layers (12).

6. The photovoltaic flexible energy storage power cable according to claim 4, characterized in that, A filling layer (13) is fixedly inserted inside the heat-conducting layer (14), and the pressure detection optical fiber (15) is fixedly inserted inside the filling layer (13).

7. The photovoltaic flexible energy storage power cable according to claim 1, characterized in that, The outer wall of the snake-bone bending mechanism (2) is fixedly fitted with a protective mechanism (3), which includes an elastic damping layer (31), a fireproof layer (32), and a protective layer (33).

8. The photovoltaic flexible energy storage power cable according to claim 7, characterized in that, The fireproof layer (32) is fixedly sleeved on the outside of the elastic damping layer (31), and a protective layer (33) is fixedly sleeved on the outer wall of the fireproof layer (32).

9. The photovoltaic flexible energy storage power cable according to claim 7, characterized in that, The protective layer (33) includes a biological repellent layer (331), a physical protective layer (332) and a reflective coating (333), and the outer wall of the biological repellent layer (331) is fixedly fitted with the physical protective layer (332).

10. The photovoltaic flexible energy storage power cable according to claim 9, characterized in that, The outer wall of the physical protective layer (332) is provided with a reflective coating (333), which contains thermochromic material components and highly reflective metal oxide particles.

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